shared/log15/stack/stack.go
func (pcs Trace) TrimRuntime() Trace {
	for len(pcs) > 0 && inGoroot(pcs[len(pcs)-1].file()) {
		pcs = pcs[:len(pcs)-1]
	}
	return pcs
}
func (pcs Trace) TrimRuntime() Trace {
	for len(pcs) > 0 && inGoroot(pcs[len(pcs)-1].file()) {
		pcs = pcs[:len(pcs)-1]
	}
	return pcs
}
// TrimRuntime returns a slice of the Trace with the topmost entries from the
// go runtime removed. It considers any calls originating from files under
// GOROOT as part of the runtime.