receive data buffer

基本解释

Since you know the client will connect and immediately send data, supplying a receive buffer can make things substantially easier.
我们知道客户端会在发出连接请求后立刻传送数据，所以如果我们准备好接收缓冲区会使事情变得更为容易。
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If it is the read half that needs to be closed, then any data existing in the receive buffer is discarded and that end of the connection is closed.
如果需要关闭读取部分，则会丢弃接收缓冲区中存在的任何数据，并关闭该端的连接。
Send function takes packets from application layer into sending buffer, and the receive function takes data from receiving buffer for the application layer.
发送函数将应用层数据包放入发送缓冲区，接收函数从接收缓冲区取得数据包。