shared/log15/stack/stack.go
func (pcs Trace) TrimAbove(pc Call) Trace {
	for len(pcs) > 0 && pcs[len(pcs)-1] != pc {
		pcs = pcs[:len(pcs)-1]
	}
	return pcs
}
func (pcs Trace) TrimAbove(pc Call) Trace {
	for len(pcs) > 0 && pcs[len(pcs)-1] != pc {
		pcs = pcs[:len(pcs)-1]
	}
	return pcs
}
// TrimAbove returns a slice of the Trace with all entries above pc removed.