RubyEventStore::Event constructor should not implicitly convert data attribute to Hash

[paneq]

I see no value in that behavior:

  class Event
    def initialize(event_id: SecureRandom.uuid, metadata: nil, data: nil)
      @event_id = event_id.to_s
      @metadata = Metadata.new(metadata.to_h)
      @data     = data.to_h
    end

Let's say you want to use ClosedStruct or Struct or OpenStruct or event a String as data. You also configured a mapper/serializer in a way which knows how to handle such classes an how to serializer/deserialize them properly. Why should RES enforce it to be a Hash? Why can it not be anything else?

The impact should be minimal in my opinion:

• the documentation shows Hashes
• the user can wrap mapper with one that does to_h conversion
• the user can add to_h calls in all places which instantiate events
• the user can use its own class inheritance to add to_h conversion and call super with modified arguments.

[fidel]

Discuss: #480