module Net::SSH::Transport::PacketStream

def next_packet(mode=:nonblock)

until a packet is available.
returned. If the mode parameter is :block, then this method will block
available or not, and will return nil if there is no packet ready to be
default), then this will return immediately, whether a packet is
Returns the next full packet. If the mode parameter is :nonblock (the 
def next_packet(mode=:nonblock)
  case mode
  when :nonblock then
    if available_for_read?
      if fill <= 0
        raise Net::SSH::Disconnect, "connection closed by remote host"
      end
    end
    poll_next_packet
  when :block then
    loop do
      packet = poll_next_packet
      return packet if packet
      loop do
        result = Net::SSH::Compat.io_select([self]) or next
        break if result.first.any?
      end
      if fill <= 0
        raise Net::SSH::Disconnect, "connection closed by remote host"
      end
    end
  else
    raise ArgumentError, "expected :block or :nonblock, got #{mode.inspect}"
  end
end