# File lib/aws/core/http/handler.rb, line 23
        def initialize(base, &block)
          @base = base
          if base.respond_to?(:handle)

            unless [2,3].include?(block.arity)
              raise ArgumentError, 'passed block must accept 2 or 3 arguments'
            end

            MetaUtils.extend_method(self, :handle, &block)

            if block.arity == 3
              m = Module.new do
                eval("def handle req, resp, &read_block\nsuper(req, resp, read_block)\nend\n")
              end
              self.extend(m)
            end

          elsif base.respond_to?(:handle_async)

            unless block.arity == 3
              raise ArgumentError, 'passed block must accept 3 arguments'
            end

            MetaUtils.extend_method(self, :handle_async) do |req, resp, handle|
              @base.handle_async(req, resp, handle)
            end
            MetaUtils.extend(self) do
              define_method(:handle) do |req, resp|
                raise "attempted to call #handle on an async handler"
              end
              define_method(:handle_async, &block)
            end

          else
            raise ArgumentError, 'base must respond to #handle or #handle_async'
          end
        end