Reading and writing can cause EPIPE and ECONNRESET to be returned in addition to io.EOF.

_, err := conn.Write(data)
if oe, ok := err.(*net.OpError); ok && (oe.Err == syscall.EPIPE || oe.Err ==
syscall.ECONNRESET) {
    return fmt.Errorf("Connection closed")
}

_, err := conn.Read(data)
oe, ok := err.(*net.OpError)
if err == io.EOF || ok && oe.Err == syscall.ECONNRESET {
    return fmt.Errorf("Connection closed")
}

This isn't the neatest solution, and if we're going to freeze and possibly internalize
syscall, this is going to have to go.

Perhaps something similar to os.IsExist? I'm thinking net.IsReset or net.IsClosed.

Or we could simply return io.EOF for both. I don't know.

And what about other operating systems? Do they have similar problems?