log.Printf("failed to generate trace: %v", err)
		}
	})
}

// traceContext is a wrapper around a traceviewer.Emitter with some additional
// information that's useful to most parts of trace viewer JSON emission.
type traceContext struct {
	*traceviewer.Emitter
	startTime trace.Time
	endTime   trace.Time
}

// elapsed returns the elapsed time between the trace time and the start time
// of the trace.

	}

	// Emit the trace event after getting gnext but before changing curg.
	// GoSwitch expects that the current G is running and that we haven't
	// switched yet for correct status emission.
	if trace.ok() {
		trace.GoSwitch(gnext, exit)
	}

	// Start running next, without heavy scheduling machinery.
	// Set mp.curg and gnext.m and then update scheduling state
	// directly if possible.