Golang net.Conn并行写入

Question

I have multiple Goroutines sharing a net.Conn object. Can they issue a Write calls simultaneously?

My main concern is that of Write calls which are partially done. Say I intend to wrote 100 bytes, but only 30 were sent, so I need to send 70 more. For this I will typically write a loop:

count := 0
for count < len(buf) {
    byteSent, err := conn.Write(buf[count:])
    //check error 

    count += byteSent
}

But I see that Go implements this loop in net.Conn.Write line number 318 and it does so by taking a lock.

However, on Windows implementation there is no such loop except that there is a call to WSASend. I do not know how WSASend behaves and could not get much from the MSDN docs

Hence the questions are:

[edit] Added 4th question

1. Do I need to acquire a lock everytime I write to socket?
2. If yes, then the purpose of acquiring the lock in Write implementation is defeated.
3. In unix implementation, does it mean that I cannot get byteSent < len(buf) unless err != nil? (I mean am I reading the code correct?)
4. Does the WSASend on Windows implements the equivalent loop in Unix implementation

Answer 1

1. The io.Write says that in case of partial write, err will be != nil

2. Found here on StackOverflow that WSASend need not have a loop around it.

3. From #1 & #2, it implies that I need not acquire lock before calling net.Conn.Write.

So my question stands answered.