Issue #8897 has been reported by Glass_saga (Masaki Matsushita).

----------------------------------------
Feature #8897: client side TCP fast open
https://bugs.ruby-lang.org/issues/8897

Author: Glass_saga (Masaki Matsushita)
Status: Open
Priority: Normal
Assignee: 
Category: ext
Target version: current: 2.1.0


I propose that ruby supports client side TCP fast open.
Attached patch defines Socket::MSG_FASTOPEN.

Example:

require "socket"

socket = Socket.new(Socket::AF_INET, Socket::SOCK_STREAM)
socket.send("foo", Socket::MSG_FASTOPEN, Socket.sockaddr_in(80, "localhost"))


-- 
http://bugs.ruby-lang.org/