Request body is an empty hash

When constructing a serialized request body, the body is empty because of these lines here:

https://github.com/microsoft/kiota-abstractions-ruby/blob/v0.14.3/lib/microsoft_kiota_abstractions/request_information.rb#L94-L107

        writer  = request_adapter.get_serialization_writer_factory().get_serialization_writer(content_type)
        @headers.try_add(@@content_type_header, content_type)
        if values != nil && values.kind_of?(Array)
          writer.write_collection_of_object_values(nil, values)
        else
          writer.write_object_value(nil, values);
        end
        this.content = writer.get_serialized_content();

The calls to writer.write_collection_of_object_values and writer.write_object_value with a nil key will return a new writer object, thus this.content = writer.get_serialized_content(); will be empty because it doesn't get written to the original writer.

The new writer objects are constructed here:

https://github.com/microsoft/kiota-serialization-json-ruby/blob/v0.7.0/lib/microsoft_kiota_serialization_json/json_serialization_writer.rb#L162-L165

    def write_object_value(key, value)
      if value
        if !key
          temp = JsonSerializationWriter.new()
          value.serialize(temp)
          return temp
        end
        begin
          temp = JsonSerializationWriter.new()
          value.serialize(temp)
          @writer[key] = temp.writer
        rescue StandardError => e
          raise e.class, "no key or value included in write_boolean_value(key, value)" 
        end
      end
    end

and here:

https://github.com/microsoft/kiota-serialization-json-ruby/blob/v0.7.0/lib/microsoft_kiota_serialization_json/json_serialization_writer.rb#L149-L152

Start in lib/microsoft_kiota_abstractions/request_information.rb around lines 94-107, then inspect the referenced write_object_value and write_collection_of_object_values methods in the JSON serialization writer. Reproduce the request-body construction and verify that serialized object and collection values are retained in the final content rather than producing an empty body.