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: domain_event.rb
    path of file: ./repos/active_event_store/lib/active_event_store
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module ActiveEventStore
  class DomainEvent < RubyEventStore::Mappers::Transformation::DomainEvent
    attr_reader :mapping
    def initialize(mapping:)
      @mapping = mapping
    end

    def dump(event)
      # lazily add type to mapping
      # NOTE: use class name instead of a class to handle code reload
      # in development (to avoid accessing orphaned classes)
      mapping.register(event.even
    
    def dump(event)
      # lazily add type to mapping
      # NOTE: use class name instead of a class to handle code reload
      # in development (to avoid accessing orphaned classes)
      mapping.register(event.event_type, event.class.name) unless mapping.exist?(event.event_type)

      metadata = event.metadata.dup.to_h
      timestamp = metadata[:timestamp]
      valid_at = metadata[:valid_at]
      RubyEventStore::Record.new(
        event_id: event.event_id,
        metadata: metadata,
        data: event.data,
        event_type: event.event_type,
        timestamp: timestamp,
        valid_at: valid_at
      )
    end