def call(*, **, &block)
      pid = fork_and_return_pid(&block)
      write.close
      result = read.read
      Process.wait(pid)

      # rubocop:disable MarshalLoad
      Marshal.load(result)
      # rubocop:enable MarshalLoad
    end
def call(*, **, &block)
      pid = fork_and_return_pid(&block)
      write.close
      result = read.read
      Process.wait(pid)

      # rubocop:disable MarshalLoad
      Marshal.load(result)
      # rubocop:enable MarshalLoad
    end
Run the block inside a subprocess, and return the value.

 @return [#object_id] The result.