class Net::SSH::Transport::Session

packets read are enqueued (see #push).
this just waits long enough to see if there are any pending packets. Any
Waits (blocks) until the given block returns true. If no block is given,

def wait
  loop do
    break if block_given? && yield
    message = poll_message(:nonblock, false)
    push(message) if message
    break if !block_given?
  end
end