onLog property
Where a formula's output goes as it is produced.
Wired to the agent's own logger, so it reaches the Hub through the node
log stream and an operator can watch an install happen instead of waiting
to be told how it went. Each line is tagged with the run that produced it
— [dart install] … — because the stream carries everything the node
says, and a reader needs to pick one run out of it.
Implementation
final void Function(String line)? onLog;