Replaces the usage of SO_SNDTIMEO with TCP_USER_TIMEOUT on Linux.
- Noted as more effective than SO_SNDTIMEO by multiple sources.
- Drops TCP connection on timeout instead of returning send() errors,
meaning more predictable reconnect timing and reconnect.
- Timeout period actually reflected in practice. SO_SNDTIMEO takes
double the timeout time than actually requested to time out on
unix, whereas WinSock actually waits the specified time.
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