coreaudio::audio_unit::render_callback::action_flags::OFFLINE_PREFLIGHT

pub const OFFLINE_PREFLIGHT: ActionFlags = ActionFlags{bits: au::kAudioOfflineUnitRenderAction_Preflight,}

This is used with offline audio units (of type 'auol'). It is used when an offline unit is being preflighted, which is performed prior to when the actual offline rendering actions are performed. It is used for those cases where the offline process needs it (for example, with an offline unit that normalizes an audio file, it needs to see all of the audio data first before it can perform its normalization).

Available in OS X v10.3 and later.