class Bundler::Settings::TCPSocketProbe

def probe_writtable_socket(socket, address)
  socket.connect_nonblock(address)
rescue Errno::EISCONN
  true
rescue StandardError # Connection failed
  false
end

def replies?(mirror)
  MirrorSockets.new(mirror).any? do |socket, address, timeout|
    socket.connect_nonblock(address)
  rescue Errno::EINPROGRESS
    wait_for_writtable_socket(socket, address, timeout)
  rescue RuntimeError # Connection failed somehow, again
    false
  end
end

def wait_for_writtable_socket(socket, address, timeout)
  if IO.select(nil, [socket], nil, timeout)
    probe_writtable_socket(socket, address)
  else # TCP Handshake timed out, or there is something dropping packets
    false
  end
end