DPL: improve signposts when processing messages

[ktf]

DPL: improve signposts when processing messages

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• -> DPL: improve signposts when processing messages #12811
• DPL: do not spin when stdout / stderr from child is not connected #12810

[github-actions]

REQUEST FOR PRODUCTION RELEASES:
To request your PR to be included in production software, please add the corresponding labels called "async-" to your PR. Add the labels directly (if you have the permissions) or add a comment of the form (note that labels are separated by a ",")

+async-label <label1>, <label2>, !<label3> ...

This will add <label1> and <label2> and removes <label3>.

The following labels are available
async-2023-pbpb-apass
async-2023-pp-apass1
async-2022-pp-apass6
async-2022-pp-apass4
async-mc
async-data

[alibuild]

Error while checking build/O2/fullCI for 771983d at 2024-03-05 23:06:

## sw/BUILD/O2-latest/log
c++: error: unrecognized command-line option '--rtlib=compiler-rt'
c++: error: unrecognized command-line option '--rtlib=compiler-rt'


## sw/BUILD/O2-full-system-test-latest/log
task timeout reached .. killing all processes


## sw/BUILD/o2checkcode-latest/log
--
========== List of errors found ==========
++ GRERR=0
++ grep -v clang-diagnostic-error error-log.txt
++ grep ' error:'
++ GRERR=1
++ [[ 1 == 0 ]]
++ mkdir -p /sw/INSTALLROOT/9074e0bcf7e95cdb3d355e3092e59ee8530b9a2d/slc8_x86-64/o2checkcode/1.0-local2077/etc/modulefiles
++ cat
--

Full log here.

[github-actions]

This PR did not have any update in the last 30 days. Is it still needed? Unless further action in will be closed in 5 days.

[github-actions]

REQUEST FOR PRODUCTION RELEASES:
To request your PR to be included in production software, please add the corresponding labels called "async-" to your PR. Add the labels directly (if you have the permissions) or add a comment of the form (note that labels are separated by a ",")

+async-label <label1>, <label2>, !<label3> ...

This will add <label1> and <label2> and removes <label3>.

The following labels are available
async-2023-pbpb-apass
async-2023-pp-apass1
async-2022-pp-apass6-2023-PbPb-apass2
async-2022-pp-apass4
async-mc
async-data

[github-actions]

This PR did not have any update in the last 30 days. Is it still needed? Unless further action in will be closed in 5 days.