diff --git a/lib/compiler/aro/main.zig b/lib/compiler/aro/main.zig
index 9e0440febfb6bf3c196dec11380c7f726e2a5812..ca079c0e5f7e12dcba64de54a07cb807cb72b4ae 100644
--- a/lib/compiler/aro/main.zig
+++ b/lib/compiler/aro/main.zig
@@ -31,7 +31,7 @@ pub fn main() u8 {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/compiler/libc.zig b/lib/compiler/libc.zig
index 1aa9a587ae32d35405a85dbd627ce6b4ebb18205..eb4614c95db3552f2e36342c4ce1ea7161347f31 100644
--- a/lib/compiler/libc.zig
+++ b/lib/compiler/libc.zig
@@ -30,7 +30,7 @@ pub fn main() !void {
     const arena = arena_instance.allocator();
     const gpa = arena;
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/compiler/objcopy.zig b/lib/compiler/objcopy.zig
index 2e272b074b83b8fc5c2cacf399303b82d72b325d..600166288c051d30e7f4dd782559514aeb48cfe7 100644
--- a/lib/compiler/objcopy.zig
+++ b/lib/compiler/objcopy.zig
@@ -148,7 +148,7 @@ fn cmdObjCopy(gpa: Allocator, arena: Allocator, args: []const []const u8) !void
     const input = opt_input orelse fatal("expected input parameter", .{});
     const output = opt_output orelse fatal("expected output parameter", .{});
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/compiler/reduce.zig b/lib/compiler/reduce.zig
index a93db3a6d7a20ac1e5d491c8dfd494c151ce8567..922031d00873a8a18cbe2d766c1b5f3b35baa98e 100644
--- a/lib/compiler/reduce.zig
+++ b/lib/compiler/reduce.zig
@@ -55,7 +55,7 @@ pub fn main() !void {
     var general_purpose_allocator: std.heap.GeneralPurposeAllocator(.{}) = .init;
     const gpa = general_purpose_allocator.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/compiler/resinator/main.zig b/lib/compiler/resinator/main.zig
index 81a3a8689a45ffcb2029c9a284ccc9c23a35111d..7e2e8403caf33abddc24f7ed0613cae9ed8a14ec 100644
--- a/lib/compiler/resinator/main.zig
+++ b/lib/compiler/resinator/main.zig
@@ -24,7 +24,7 @@ pub fn main() !void {
     defer std.debug.assert(debug_allocator.deinit() == .ok);
     const gpa = debug_allocator.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/compiler/translate-c/main.zig b/lib/compiler/translate-c/main.zig
index 76d67afd1819112a9bfc7af6685bf57d14bbade1..a6737b68fa7b8dfe77494d25355d4f98ff92ac14 100644
--- a/lib/compiler/translate-c/main.zig
+++ b/lib/compiler/translate-c/main.zig
@@ -19,7 +19,7 @@ pub fn main() u8 {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/init/src/main.zig b/lib/init/src/main.zig
index 9df441b56468877f4f8a1a1869827fb6b4c44677..865e6c53228c9c69f441eec4427656d671cb9ce3 100644
--- a/lib/init/src/main.zig
+++ b/lib/init/src/main.zig
@@ -13,7 +13,7 @@ pub fn main() !void {
     const gpa = debug_allocator.allocator();
 
     // In order to do I/O operations we must construct an `Io` instance.
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/lib/std/crypto/benchmark.zig b/lib/std/crypto/benchmark.zig
index 1b71110be52623ba22d58e438a695736cc03e3a8..23154324bc280d8b54d45c032de56c60670ac5ba 100644
--- a/lib/std/crypto/benchmark.zig
+++ b/lib/std/crypto/benchmark.zig
@@ -556,7 +556,7 @@ pub fn main() !void {
         }
     }
 
-    var io_threaded = std.Io.Threaded.init(arena_allocator);
+    var io_threaded = std.Io.Threaded.init(arena_allocator, .{});
     defer io_threaded.deinit();
     const io = io_threaded.io();
 
diff --git a/src/Package/Fetch/git.zig b/src/Package/Fetch/git.zig
index 0cb7e6230080e081c2152dc1a9ec0966c15275e6..18e15f457f0135b77117922119660b4a81a4c3ac 100644
--- a/src/Package/Fetch/git.zig
+++ b/src/Package/Fetch/git.zig
@@ -1702,7 +1702,7 @@ test "SHA-256 packfile indexing and checkout" {
 pub fn main() !void {
     const allocator = std.heap.smp_allocator;
 
-    var threaded: Io.Threaded = .init(allocator);
+    var threaded: Io.Threaded = .init(allocator, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/src/fmt.zig b/src/fmt.zig
index ca6885d24e01d6a3215f8b7a8739660f7bdb287a..b1903aad5370ad17f03db0397ea3572621827593 100644
--- a/src/fmt.zig
+++ b/src/fmt.zig
@@ -370,7 +370,7 @@ pub fn main() !void {
     var arena_instance = std.heap.ArenaAllocator.init(gpa);
     const arena = arena_instance.allocator();
     const args = try process.argsAlloc(arena);
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
     return run(gpa, arena, io, args[1..]);
diff --git a/test/src/convert-stack-trace.zig b/test/src/convert-stack-trace.zig
index 272edad18ed8d063144c34b36f0757011d47df6c..d23623c396826b9488a75eb67dcb2a3fb5137567 100644
--- a/test/src/convert-stack-trace.zig
+++ b/test/src/convert-stack-trace.zig
@@ -34,7 +34,7 @@ pub fn main() !void {
 
     const gpa = arena;
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/child_process/child.zig b/test/standalone/child_process/child.zig
index 5dbf95af4c0bbf74018bb3af50075b7a077d85bb..1bd97bace6716d845adfeb9612e9e0c0c941fc15 100644
--- a/test/standalone/child_process/child.zig
+++ b/test/standalone/child_process/child.zig
@@ -8,7 +8,7 @@ pub fn main() !void {
     var arena_state = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     const arena = arena_state.allocator();
 
-    var threaded: std.Io.Threaded = .init(arena);
+    var threaded: std.Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/child_process/main.zig b/test/standalone/child_process/main.zig
index 3aaec0f2b232cd7c7044e368b526dc42a83b4bb0..372ef01ce829c1f3c17e82d71741a1bd3ae812b1 100644
--- a/test/standalone/child_process/main.zig
+++ b/test/standalone/child_process/main.zig
@@ -21,7 +21,7 @@ pub fn main() !void {
     };
     defer if (needs_free) gpa.free(child_path);
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/coff_dwarf/main.zig b/test/standalone/coff_dwarf/main.zig
index e7590f3f0746b53ce90725084158909826b8eb40..7e314d5b287cb781791474a12e599ff5d6b0b175 100644
--- a/test/standalone/coff_dwarf/main.zig
+++ b/test/standalone/coff_dwarf/main.zig
@@ -11,7 +11,7 @@ pub fn main() void {
     var di: std.debug.SelfInfo = .init;
     defer di.deinit(gpa);
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/libfuzzer/main.zig b/test/standalone/libfuzzer/main.zig
index 077af4ad3eb171f3ea0f2666d968e141071ddd71..0bc093d8705ba63221cd87114931a0fc3e8f0bbc 100644
--- a/test/standalone/libfuzzer/main.zig
+++ b/test/standalone/libfuzzer/main.zig
@@ -15,7 +15,7 @@ pub fn main() !void {
     defer args.deinit();
     _ = args.skip(); // executable name
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/self_exe_symlink/main.zig b/test/standalone/self_exe_symlink/main.zig
index dfe3acb7a0b8f99ee0ce0f2f79aa66ad6fee196f..0f9455e3a43fd452dc55db80b3e8d70022710a1f 100644
--- a/test/standalone/self_exe_symlink/main.zig
+++ b/test/standalone/self_exe_symlink/main.zig
@@ -5,7 +5,7 @@ pub fn main() !void {
     defer if (debug_allocator.deinit() == .leak) @panic("found memory leaks");
     const gpa = debug_allocator.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/simple/cat/main.zig b/test/standalone/simple/cat/main.zig
index 699fc8075da282815d3204416a6194ebd23587e7..0135ac4b50943e5fc4c2fe136ea611fc20bc70cf 100644
--- a/test/standalone/simple/cat/main.zig
+++ b/test/standalone/simple/cat/main.zig
@@ -9,7 +9,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: std.Io.Threaded = .init(arena);
+    var threaded: std.Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/simple/hello_world/hello.zig b/test/standalone/simple/hello_world/hello.zig
index 6bce8413441ed0421687c90deb058bf7b3fa16d2..7bb4f00e4dd87b876a3c68ab2dd18038b2719bfe 100644
--- a/test/standalone/simple/hello_world/hello.zig
+++ b/test/standalone/simple/hello_world/hello.zig
@@ -5,7 +5,7 @@ pub fn main() !void {
     defer _ = debug_allocator.deinit();
     const gpa = debug_allocator.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/test/standalone/windows_bat_args/fuzz.zig b/test/standalone/windows_bat_args/fuzz.zig
index 6c89c50e0bb87b4821e386fd6d0855be1ecf22ae..db6043d3e9a41cd7d81496b3feb41e36c2e916fa 100644
--- a/test/standalone/windows_bat_args/fuzz.zig
+++ b/test/standalone/windows_bat_args/fuzz.zig
@@ -9,7 +9,7 @@ pub fn main() anyerror!void {
     defer std.debug.assert(debug_alloc_inst.deinit() == .ok);
     const gpa = debug_alloc_inst.allocator();
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     const io = threaded.io();
 
     var it = try std.process.argsWithAllocator(gpa);
diff --git a/test/standalone/windows_bat_args/test.zig b/test/standalone/windows_bat_args/test.zig
index 4630fa33373c309102b1a5d5b13261626bceba8a..48c32826e5cb381c21904fb52cadf923e3b991c8 100644
--- a/test/standalone/windows_bat_args/test.zig
+++ b/test/standalone/windows_bat_args/test.zig
@@ -7,7 +7,7 @@ pub fn main() anyerror!void {
     defer std.debug.assert(debug_alloc_inst.deinit() == .ok);
     const gpa = debug_alloc_inst.allocator();
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     const io = threaded.io();
 
     var it = try std.process.argsWithAllocator(gpa);
diff --git a/test/standalone/windows_spawn/main.zig b/test/standalone/windows_spawn/main.zig
index 569eba04070ada74ad1060e8e904201b869f4d73..db771c88eb95617ad5ddabdc6927851d99a9bf5b 100644
--- a/test/standalone/windows_spawn/main.zig
+++ b/test/standalone/windows_spawn/main.zig
@@ -10,7 +10,7 @@ pub fn main() anyerror!void {
     defer if (debug_allocator.deinit() == .leak) @panic("found memory leaks");
     const gpa = debug_allocator.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/docgen.zig b/tools/docgen.zig
index 11cd40acde4b77bd14a9118a4177c2321066b22c..a46e34ee7e7a0a05285f8e7ad3c1a13b4cda7118 100644
--- a/tools/docgen.zig
+++ b/tools/docgen.zig
@@ -38,7 +38,7 @@ pub fn main() !void {
 
     const gpa = arena;
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/doctest.zig b/tools/doctest.zig
index b7219c53f0110a2329e9a5a32ed0eb928e5960c9..8dffd447a4b7351e2d2dba37bcc9a7076ec3d77f 100644
--- a/tools/doctest.zig
+++ b/tools/doctest.zig
@@ -40,7 +40,7 @@ pub fn main() !void {
 
     const gpa = arena;
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/dump-cov.zig b/tools/dump-cov.zig
index 3dd91de6122a786ad8e15bd9f621d8065ae117fd..d52b61f0583b753c0940c124b625d5c2c3238b65 100644
--- a/tools/dump-cov.zig
+++ b/tools/dump-cov.zig
@@ -16,7 +16,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/fetch_them_macos_headers.zig b/tools/fetch_them_macos_headers.zig
index 6575aa2b566ee713b4d675e1bd6437ce5d31102a..815042e3af3b2092fa64ade895af6f03319f2eb8 100644
--- a/tools/fetch_them_macos_headers.zig
+++ b/tools/fetch_them_macos_headers.zig
@@ -86,7 +86,7 @@ pub fn main() anyerror!void {
         } else try argv.append(arg);
     }
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/gen_macos_headers_c.zig b/tools/gen_macos_headers_c.zig
index 62ae815da31c3ae8720011f4788076b3d3084ebb..657bda8ab2342850aee37fe348274499b462df9f 100644
--- a/tools/gen_macos_headers_c.zig
+++ b/tools/gen_macos_headers_c.zig
@@ -21,7 +21,7 @@ pub fn main() anyerror!void {
     defer arena_allocator.deinit();
     const arena = arena_allocator.allocator();
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/generate_c_size_and_align_checks.zig b/tools/generate_c_size_and_align_checks.zig
index 3663756533ef4bd8595932e6f359267bb2d96b61..6f934564066ecc1fd43d6bfb04105644baacd996 100644
--- a/tools/generate_c_size_and_align_checks.zig
+++ b/tools/generate_c_size_and_align_checks.zig
@@ -39,7 +39,7 @@ pub fn main() !void {
         std.process.exit(1);
     }
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/generate_linux_syscalls.zig b/tools/generate_linux_syscalls.zig
index b3e5d623778108651e0c05aa5c0e5c81c4924bb9..789cb95116781a817e1c27f867ce412e1b0a0ee0 100644
--- a/tools/generate_linux_syscalls.zig
+++ b/tools/generate_linux_syscalls.zig
@@ -175,7 +175,7 @@ pub fn main() !void {
     defer arena.deinit();
     const gpa = arena.allocator();
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/incr-check.zig b/tools/incr-check.zig
index b9c9eb0e92757a6319205dd216b497c507fced1e..15e5d009150242d89cf350071007a20532c39e80 100644
--- a/tools/incr-check.zig
+++ b/tools/incr-check.zig
@@ -15,7 +15,7 @@ pub fn main() !void {
 
     const gpa = arena;
 
-    var threaded: Io.Threaded = .init(gpa);
+    var threaded: Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/migrate_langref.zig b/tools/migrate_langref.zig
index e03e266c2e873c60c0319637f3a18b219671fa9c..299326d98c7d0ecaaf39d4faa0d508c99761d79a 100644
--- a/tools/migrate_langref.zig
+++ b/tools/migrate_langref.zig
@@ -22,7 +22,7 @@ pub fn main() !void {
     const input_file = args[1];
     const output_file = args[2];
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update-linux-headers.zig b/tools/update-linux-headers.zig
index 4faf9b27488420355acee603a5585dc83880704e..2d71d8c71864a55a0199f03300863e393a998f84 100644
--- a/tools/update-linux-headers.zig
+++ b/tools/update-linux-headers.zig
@@ -145,7 +145,7 @@ pub fn main() !void {
     var arena_state = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     const arena = arena_state.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_cpu_features.zig b/tools/update_cpu_features.zig
index 3741e51d3c4fd539b42cbe2dfa674af93fa1d796..e49ca4d01a795b4d62c67f01f6c2854548ee1df5 100644
--- a/tools/update_cpu_features.zig
+++ b/tools/update_cpu_features.zig
@@ -1892,7 +1892,7 @@ pub fn main() anyerror!void {
     defer arena_state.deinit();
     const arena = arena_state.allocator();
 
-    var threaded: std.Io.Threaded = .init(gpa);
+    var threaded: std.Io.Threaded = .init(gpa, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_crc_catalog.zig b/tools/update_crc_catalog.zig
index 2893f70f674deaacf67e22183ac41765047a5229..16ae58a564350b7f0e79d99154b493326311632b 100644
--- a/tools/update_crc_catalog.zig
+++ b/tools/update_crc_catalog.zig
@@ -11,7 +11,7 @@ pub fn main() anyerror!void {
     defer arena_state.deinit();
     const arena = arena_state.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_freebsd_libc.zig b/tools/update_freebsd_libc.zig
index c43b94858db29d5905cee34e1bdf528440008504..9a3bd3ee78ef311408a65484b8f29eb650c65c30 100644
--- a/tools/update_freebsd_libc.zig
+++ b/tools/update_freebsd_libc.zig
@@ -17,7 +17,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_glibc.zig b/tools/update_glibc.zig
index 227400476201db69400ffba676de2d2b7104ee9f..1a92bda1dbdd5875d94434c048c6fceeb6f09637 100644
--- a/tools/update_glibc.zig
+++ b/tools/update_glibc.zig
@@ -43,7 +43,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_mingw.zig b/tools/update_mingw.zig
index fee5774629b83edffe74e9a6a83d8b3a3f120c9c..d427a41e74c16fbad37f3eb84f3cbe95805aad56 100644
--- a/tools/update_mingw.zig
+++ b/tools/update_mingw.zig
@@ -7,7 +7,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();
 
diff --git a/tools/update_netbsd_libc.zig b/tools/update_netbsd_libc.zig
index e3b7bd21eed32dc2d7f5e96e17a389f574758a85..31f77daf51ec0f0e3fd4b4f95f3df25243851b88 100644
--- a/tools/update_netbsd_libc.zig
+++ b/tools/update_netbsd_libc.zig
@@ -17,7 +17,7 @@ pub fn main() !void {
     defer arena_instance.deinit();
     const arena = arena_instance.allocator();
 
-    var threaded: Io.Threaded = .init(arena);
+    var threaded: Io.Threaded = .init(arena, .{});
     defer threaded.deinit();
     const io = threaded.io();