golang获取udp套接字缓冲区大小

I'm writing a udp client and set udp socket send buffer by SetWriteBuffer.

   addr, _ := net.ResolveUDPAddr("udp", ":8089")
   conn, err :=net.DialUDP("udp", nil, addr)  
   err =conn.SetWriteBuffer(64*1024*1024)

as above, how can I test set the value is effective or get the send buffer value after call SetWriteBuffer function.
Thank you all.

After looking at the net package code, it looks like SetWriteBuffer makes a syscall to setsockopt (for posix). There is no similar function for GetWriteBuffer. The only way i can think to do this is by making another syscall to getsockopt like so.

addr, _ := net.ResolveUDPAddr("udp", ":8089")
conn, _ := net.DialUDP("udp", nil, addr)
conn.SetWriteBuffer(10 * 1024)
fd, _ := conn.File()
value, _ := syscall.GetsockoptInt(int(fd.Fd()), syscall.SOL_SOCKET, syscall.SO_SNDBUF)
log.Println(value)
fd.Close()
conn.Close()

Check the error value returned by SetWriteBuffer. For example,

package main

import (
    "log"
    "net"
)

func main() {
    addr, err := net.ResolveUDPAddr("udp", ":8089")
    conn, err := net.DialUDP("udp", nil, addr)

    err = conn.SetWriteBuffer(64 * 1024 * 1024)
    if err != nil {
        log.Print(err)
    }
}