debugSfxDisposeCount property
Count of SFX AudioPlayers actually disposed — a player is only ever
disposed when _sfxPool evicts one over sfxPoolCapacity (a burst
wider than the pool) or on onClose's full teardown; every ordinary
playSfx call now returns its player to the pool instead (BUG-24's
original "dispose every call" guarantee is superseded by
debugSfxReleaseCount/debugSfxPoolActiveCount below — those, not
this, are what prove a call doesn't leak post-ENH-79).
Implementation
@visibleForTesting
int debugSfxDisposeCount = 0;