// library. However, that library will poll with 100ms fixed interval. Often the cache syncs in a few
// ms, but we are delayed a full 100ms. This is especially apparent in tests, which previously spent
// most of their time just in the 100ms wait interval.
//
// To optimize this, this function performs exponential backoff. This is generally safe because

	// support shutdown signals but are expected to always finish quickly.
	//
	// Cancel will not be called if Start returns a non-nil error.
	Cancel func() error

	// If WaitDelay is non-zero, it bounds the time spent waiting on two sources
	// of unexpected delay in Wait: a child process that fails to exit after the
	// associated Context is canceled, and a child process that exits but leaves
	// its I/O pipes unclosed.
	//