rbuf_fill

# File lib/net/protocol.rb, line 151
    def rbuf_fill
      begin
        @rbuf << @io.read_nonblock(BUFSIZE)
      rescue IO::WaitReadable
        if IO.select([@io], nil, nil, @read_timeout)
          retry
        else
          raise Net::ReadTimeout
        end
      rescue IO::WaitWritable
        # OpenSSL::Buffering#read_nonblock may fail with IO::WaitWritable.
        # http://www.openssl.org/support/faq.html#PROG10
        if IO.select(nil, [@io], nil, @read_timeout)
          retry
        else
          raise Net::ReadTimeout
        end
      end
    end