diff --git a/src/chrome.zig b/src/chrome.zig
index db54400d5ebfe61c19d3836de084c39683e1b33b..c58a4a4b939ac6d7ffbd8fb4e71966ce35f0a878 100644
--- a/src/chrome.zig
+++ b/src/chrome.zig
@@ -42,7 +42,7 @@ pub fn deinit_thread() void {
     buffered_writer.flush() catch {};
 }
 
-pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: anytype) void {
+pub inline fn trace_begin(src: std.builtin.SourceLocation, comptime ifmt: []const u8, iargs: anytype) void {
     buffered_writer.print(
         \\{{"cat":"function", "name":"{s}:{d}:{d} ({s})
     ++ ifmt ++
@@ -50,10 +50,10 @@ pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: any
         \\
     ,
         .{
-            ctx.src.file,
-            ctx.src.line,
-            ctx.src.column,
-            ctx.src.fn_name,
+            src.file,
+            src.line,
+            src.column,
+            src.fn_name,
         } ++ iargs ++ .{
             pid,
             tid,
@@ -75,3 +75,5 @@ pub inline fn trace_end(ctx: tracer.Ctx) void {
         },
     ) catch {};
 }
+
+pub const Data = void;
diff --git a/src/log.zig b/src/log.zig
index 5eb0b88e55e8b9e3a570f4cc4cc9e5bd5ca12f52..3bd006c2a6ed8c4215b36af6e79ac45e05e5bab4 100644
--- a/src/log.zig
+++ b/src/log.zig
@@ -14,10 +14,12 @@ pub fn init_thread(args: struct {}) !void {
 
 pub fn deinit_thread() void {}
 
-pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: anytype) void {
-    log.debug("{s}:{d}:{d} ({s})" ++ ifmt, .{ ctx.src.file, ctx.src.line, ctx.src.column, ctx.src.fn_name } ++ iargs);
+pub inline fn trace_begin(src: std.builtin.SourceLocation, comptime ifmt: []const u8, iargs: anytype) void {
+    log.debug("{s}:{d}:{d} ({s})" ++ ifmt, .{ src.file, src.line, src.column, src.fn_name } ++ iargs);
 }
 
 pub inline fn trace_end(ctx: tracer.Ctx) void {
     _ = ctx;
 }
+
+pub const Data = void;
diff --git a/src/mod.zig b/src/mod.zig
index ba675c05440cad2ceeb77f6f18230e6e3b21537a..5676eb5928b145fe066386adc46a5c79598d5dc8 100644
--- a/src/mod.zig
+++ b/src/mod.zig
@@ -4,8 +4,6 @@ const extras = @import("extras");
 const nfs = @import("nfs");
 const impl = extras.globalOption("tracer_impl", type) orelse none;
 
-threadlocal var started = false;
-
 pub const none = @import("./none.zig");
 pub const log = @import("./log.zig");
 pub const chrome = @import("./chrome.zig");
@@ -21,26 +19,24 @@ pub fn deinit() void {
 
 pub fn init_thread(args: @typeInfo(@TypeOf(impl.init_thread)).@"fn".params[0].type.?) !void {
     try impl.init_thread(args);
-    started = true;
 }
 
 pub fn deinit_thread() void {
     impl.deinit_thread();
-    started = false;
 }
 
 pub inline fn trace(src: std.builtin.SourceLocation, comptime fmt: []const u8, args: anytype) Ctx {
-    const ctx = Ctx{
+    return .{
         .src = src,
+        .data = impl.trace_begin(src, fmt, args),
     };
-    if (started) impl.trace_begin(ctx, fmt, args);
-    return ctx;
 }
 
 pub const Ctx = struct {
     src: std.builtin.SourceLocation,
+    data: impl.Data,
 
     pub inline fn end(self: Ctx) void {
-        if (started) impl.trace_end(self);
+        impl.trace_end(self);
     }
 };
diff --git a/src/none.zig b/src/none.zig
index e9034a9e3b978fa44ce3b6b2220a89c4305754ff..842ca9f741985f73f461982219bdf0b95f4be788 100644
--- a/src/none.zig
+++ b/src/none.zig
@@ -14,8 +14,8 @@ pub fn init_thread(args: struct {}) !void {
 
 pub fn deinit_thread() void {}
 
-pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: anytype) void {
-    _ = ctx;
+pub inline fn trace_begin(src: std.builtin.SourceLocation, comptime ifmt: []const u8, iargs: anytype) void {
+    _ = src;
     _ = ifmt;
     _ = iargs;
 }
@@ -23,3 +23,5 @@ pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: any
 pub inline fn trace_end(ctx: tracer.Ctx) void {
     _ = ctx;
 }
+
+pub const Data = void;
diff --git a/src/spall.zig b/src/spall.zig
index 406c9e1c996cb5420971116b43b3e52a2da57705..1ed28330f3084366d199950997adb45e840bc676 100644
--- a/src/spall.zig
+++ b/src/spall.zig
@@ -41,9 +41,9 @@ pub fn deinit_thread() void {
     buffered_writer.flush() catch {};
 }
 
-pub inline fn trace_begin(ctx: tracer.Ctx, comptime ifmt: []const u8, iargs: anytype) void {
+pub inline fn trace_begin(src: std.builtin.SourceLocation, comptime ifmt: []const u8, iargs: anytype) void {
     const fmt = "{s}:{d}:{d} ({s})" ++ ifmt;
-    const args = .{ ctx.src.file, ctx.src.line, ctx.src.column, ctx.src.fn_name };
+    const args = .{ src.file, src.line, src.column, src.fn_name };
     buffered_writer.writeStruct(BeginEvent{
         .pid = @intCast(pid),
         .tid = @intCast(tid),
@@ -63,6 +63,8 @@ pub inline fn trace_end(ctx: tracer.Ctx) void {
     }) catch return;
 }
 
+pub const Data = void;
+
 // https://github.com/colrdavidson/spall-web/blob/1d4610a1fe9aaaf2e071327a1142a498f3436bdc/formats/spall/spall.odin
 // https://github.com/colrdavidson/spall-web/blob/1d4610a1fe9aaaf2e071327a1142a498f3436bdc/tools/json2bin/json2bin.odin
 // https://github.com/colrdavidson/spall-web/blob/1d4610a1fe9aaaf2e071327a1142a498f3436bdc/tools/upconvert/main.odin