pipeline doesn't respect (at least) first message delay option

[metheoryt]

if i create pipeline as below and try to run it:

pipe = actor.message_with_options(delay=60_000) | actor.message()
pipe.run()

the pipe will be executed immediately though.
I think, pipeline should respect message delays, so e.g. if both first message delay and pipe depay specified, they should summarize.

[synweap15]

I think currently only the pipe.run(delay=60_000) invocation will take effect, the delay parameter of messages will be ignored:

1. For the first message in a pipe, the run method named argument is taken, the message's one isn't considered:
   

   dramatiq/dramatiq/composition.py

   Line 111 in 9526678

   self.broker.enqueue(self.messages[0], delay=delay)

2. For next-in-line messages, there's no delay taken into consideration:
   

   dramatiq/dramatiq/middleware/pipelines.py

   Line 56 in 843bc18

   broker.enqueue(next_message)

I've got test cases and a fix ready, however in contrast to what @metheoryt proposes, I think it would be best to follow this logic:

1. If there's either a delay specified for the first message or there's a delay specified in pipe run invocation, take the one that's present
2. If they are both present, take the one that's bigger (instead of adding them).

And of course, the messages after the first message in a pipe should have their delays respected as well.

The delay parameter of a pipeline is specified as The minimum amount of time, in milliseconds, the pipeline should be delayed by., so I think taking the bigger value of the pipeline's delay and the first message's delay would be reasonable. What do you think?