`build_runner` stuck

[zjiekai]

I'm at b5cca6d212aa8920bc93c81ac18d213f8348d06f.

I run $ flutter -v pub run build_runner build.

It seems stuck.

[INFO] 2m 6s elapsed, 1/15 actions completed.
[INFO] 2m 7s elapsed, 1/15 actions completed.
[INFO] 2m 8s elapsed, 1/15 actions completed.
[INFO] 2m 9s elapsed, 1/15 actions completed.
[INFO] 2m 10s elapsed, 1/15 actions completed.
[INFO] 2m 11s elapsed, 1/15 actions completed.
[INFO] 2m 12s elapsed, 1/15 actions completed.
[INFO] 2m 13s elapsed, 1/15 actions completed.
[INFO] 2m 14s elapsed, 1/15 actions completed.
[INFO] 2m 15s elapsed, 1/15 actions completed.
[WARNING] No actions completed for 15.1s, waiting on:
  - built_value_generator:built_value on test/json_test.dart
  - built_value_generator:built_value on test/widget_test.dart
  - built_value_generator:built_value on lib/main.dart
  - built_value_generator:built_value on lib/src/article.dart
  - built_value_generator:built_value on lib/src/widgets/search.dart
  .. and 9 more

[INFO] 2m 17s elapsed, 1/15 actions completed.
[INFO] 2m 19s elapsed, 1/15 actions completed.
[INFO] 2m 20s elapsed, 1/15 actions completed.
[INFO] 2m 21s elapsed, 1/15 actions completed.
[INFO] 2m 22s elapsed, 1/15 actions completed.
[INFO] 2m 23s elapsed, 1/15 actions completed.
[INFO] 2m 24s elapsed, 1/15 actions completed.