[FEATURE] Asynchronous publishing in nextflow

[DriesSchaumont]

Feature summary

Currently, the output of a pipeline is only published after the last component of the nextflow workflow has finished.
However, asynchronous publishing is something that could be very beneficial (both from the user perspective, for development and for performance)

Feature description

Allow publishing midway to the pipeline

Why is this feature beneficial?

See above

Alternatives considered

None

Possible solution

Allowing using multiple output channels in emit:

workflow test{
   take:
      foo
   main:
      qc_channel = ...
      final_output  = qc_channel
          | ...
   emit: 
       qc_channel
       final_output
}

Viash would then be able to concat qc_channel and final_output?
concat(test.out)

Confirmation

• I have searched the existing issues to make sure this is not a duplicate request.
• I have provided clear and concise information about the feature.