seq

The seq proc is used to serialize the execution of N flume pipelines so that they execute in the same order that you've passed them to the seq proc.

...  | seq(*pipelines) | ...

Argument	Description	Required?
*pipelines	list of flume pipelines to execute serially	Yes

serialize the execution of two emits

from flume import *

(
    seq(emit(limit=5, every='1s'),
        emit(limit=5, every='0.5s'))
    | write('stdio')
).execute()

The above would produce the output:

{"time": "2016-08-12T22:03:06.156Z"}
{"time": "2016-08-12T22:03:07.156Z"}
{"time": "2016-08-12T22:03:08.156Z"}
{"time": "2016-08-12T22:03:09.156Z"}
{"time": "2016-08-12T22:03:10.156Z"}
{"time": "2016-08-12T22:03:11.167Z"}
{"time": "2016-08-12T22:03:11.667Z"}
{"time": "2016-08-12T22:03:12.167Z"}
{"time": "2016-08-12T22:03:12.667Z"}
{"time": "2016-08-12T22:03:13.167Z"}

And you'll see how your stream will emit 1 point per second for 5s and then another 5 points in half that time. Which is a small example of how the seq proc can be useful.