Avoid SIGPIPE and polite kill child process.

SIGPIPE when using send method and remote side closed connection.

Portable alternatives: sighandler for SIGPIPE or block/ignore SIGPIPE. In some situations we
may not ignore SIGPIPE (if we are writing some API we may not just swallow SIGPIPE) because of that
depending o the situation we could ignore or block SIGPIPE.
There is SIGPIPE JUST when using send/write (no with read/recv) and remote side closed connection.