introduce a shared state for all tasks of a graph

6 jobs for !12 with 3-ignore-proces in 43 seconds (queued for 3 seconds)
latest detached
Status Name Job ID Coverage
  Style
passed black #234719

00:00:12

passed flake8 #234718

00:00:11

 
  Test
passed test-3.6 #234720

00:00:29

83.0%
passed test-3.7 #234721

00:00:29

83.0%
passed test-3.8 #234722

00:00:29

84.0%
passed test-3.9 #234723

00:00:28

84.0%