// but allowing it is convenient for testing and for programs
	// that do an os.Setenv in main.init or main.main.
	asynctimerchan atomic.Int32
}

var dbgvars = []*dbgVar{
	{name: "adaptivestackstart", value: &debug.adaptivestackstart},
	{name: "asyncpreemptoff", value: &debug.asyncpreemptoff},
	{name: "asynctimerchan", atomic: &debug.asynctimerchan},
	{name: "cgocheck", value: &debug.cgocheck},

// startingStackSize is updated every GC by tracking the average size of
// stacks scanned during the GC.
var startingStackSize uint32 = fixedStack

func gcComputeStartingStackSize() {
	if debug.adaptivestackstart == 0 {
		return
	}
	// For details, see the design doc at
	// https://docs.google.com/document/d/1YDlGIdVTPnmUiTAavlZxBI1d9pwGQgZT7IKFKlIXohQ/edit?usp=sharing