abortBreak

End the in-progress break NOW because it was REMOVED from a polled manifest — the manifest spec's "early return". Same balanced cut path as skipBreak (adend + adbreakend), with two differences the renderer must honor: content resumes at break.start + resumeOffsetSec (the seconds the break already played — overriding the DAR/DAI defaults and forcing the seek in replacement mode), and a chained successor must NOT begin now (the scheduler triggers it at its own start time). No-op when no break is playing. Default no-op so fakes need not override.