Created by: abhinavarora

Fixes https://github.com/PaddlePaddle/Paddle/issues/8812

Like Go, we will also have one single implementation for both buffered and unbuffered channels. References:

1. Channel Send - https://github.com/golang/go/blob/master/src/runtime/chan.go#L140
2. Channel Receive - https://github.com/golang/go/blob/master/src/runtime/chan.go#L417
3. Channel Close - https://github.com/golang/go/blob/master/src/runtime/chan.go#L327