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: core.rb
    path of file: ./repos/concurrent-ruby/lib/concurrent-ruby-edge/concurrent/actor
    
    the code of the file until where you have to start completion: require 'set'
require 'concurrent/actor/type_check'
require 'concurrent/concern/logging'
require 'concurrent/executors'
require 'concurrent/synchronization/lockable_object'

module Concurrent
  module Actor
    # Core of the actor.
    # @note Whole class should be considered private. An user should use {Conte
    
      def on_envelope(envelope)
        log(DEBUG) { "is  #{envelope.future ? 'asked' : 'told'} #{envelope.message.inspect} by #{envelope.sender}" }
        schedule_execution do
          log(DEBUG) { "was #{envelope.future ? 'asked' : 'told'} #{envelope.message.inspect} by #{envelope.sender} - processing" }
          process_envelope envelope
        end
        nil
      end