You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sample_ipc_http_server.rb
    path of file: ./repos/avro/lang/ruby/test
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional info
    
  def do_POST(req, resp)
    responder = MailResponder.new
    call_request = Avro::IPC::FramedReader.new(StringIO.new(req.body)).read_framed_message
    unframed_resp = responder.respond(call_request)
    writer = Avro::IPC::FramedWriter.new(StringIO.new)
    writer.write_framed_message(unframed_resp)
    resp.body = writer.to_s
  end