func (stack *Stack) Peek() (interface{}, bool) {
	stack.key.RLock()
	defer stack.key.RUnlock()
	return stack.underlyer.PeekFront()
}
func (stack *Stack) Peek() (interface{}, bool) {
	stack.key.RLock()
	defer stack.key.RUnlock()
	return stack.underlyer.PeekFront()
}
func ( stack * Stack ) Peek ( ) ( interface { } , bool ) { stack . key . RLock ( ) defer stack . key . RUnlock ( ) return stack . underlyer . PeekFront ( ) }
// Peek returns the entry at the top of the Stack without removing it.
Peek returns the entry at the top of the Stack without removing it .