output

huge_string.size
=> 65550

data.size
=> 65536
data.include? "ends in awesome"
=> false

ruby.rb

huge_string = "B" * 0xFFFF
huge_string << "ends in awesome"

data = ""

Thread.new { sleep 5; data = io_out.read_all }

io_in.puts huge_string


#################################################

# for io_out; read_all is:

      def has_data?(timeout = 0)
        IO.select([self], nil, nil, timeout) ? true : false
      end

      def read_all opts = {}
        opts[:nonblocking] ||=  false
        return nil if opts[:nonblocking] && !has_data?

        # Block until data has arrived.
        data =  readpartial 0xFFFF
        # If there is more data in the buffer, retrieve it nonblocking.
        data += readpartial 0xFFFF while has_data?
        data
      end