Who ran the attempt: the engine, for a stage's own policy ('stage'); the attempt runner, for a call a stage made
through scope.$call or for the standalone attempt() ('call'); an outside system on its own — an SDK's
internal retry — reported through AttemptContext.observed ('observed', P2).
Who ran the attempt: the engine, for a stage's own policy (
'stage'); the attempt runner, for a call a stage made throughscope.$callor for the standaloneattempt()('call'); an outside system on its own — an SDK's internal retry — reported throughAttemptContext.observed('observed', P2).