support scan

[chenjian24]

可否支持scan指令

[NaNShaner]

@HDT3213 游标的实现上可以使用ConcurrentDict.table的下标么？参考ForEach

func (dict *ConcurrentDict) ForEach(consumer Consumer) {
	if dict == nil {
		panic("dict is nil")
	}

	for _, s := range dict.table {
		s.mutex.RLock()
		f := func() bool {
			defer s.mutex.RUnlock()
			for key, value := range s.m {
				continues := consumer(key, value)
				if !continues {
					return false
				}
			}
			return true
		}
		if !f() {
			break
		}
	}
}

[HDT3213]

@NaNShaner 可以

[HDT3213]

#225