openairplay2 0.3.0

Embeddable AirPlay 2 audio receiver library (network in, PCM + events out)
Documentation 
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//! Session events delivered to the host.
//!
//! Sent over an unbounded `tokio::sync::mpsc` channel so the host consumes
//! them at its own pace; a dropped receiver is tolerated (events are then
//! discarded). Wire concepts (plists, sequence numbers, `shk`) never appear
//! here.

/// What the host needs to know about the streaming session. Transport
/// control (pause, seek) is already handled inside the library — those
/// variants are informational.
#[non_exhaustive]
#[derive(Debug, Clone, PartialEq)]
pub enum Event {
    /// `SETUP` phase 2 completed; a sink is about to be created and used.
    SessionStarted {
        /// Sample rate in Hz (currently always 44100).
        rate: u32,
        /// Channel count (currently always 2).
        channels: u8,
    },
    /// `SET_PARAMETER volume`, in AirPlay dB (0 = full, −144 = mute). The
    /// library does not apply gain — the host maps this onto its own volume
    /// model.
    Volume {
        /// AirPlay volume in dB: 0 = full scale, −30 ≈ minimum, −144 = mute.
        db: f32,
    },
    /// `SET_PARAMETER` track metadata (DMAP). A complete statement about
    /// the current track, not a delta: fields the sender's payload did not
    /// carry are `None` and replace the previous value. Delivered only
    /// between [`Event::SessionStarted`] and [`Event::SessionEnded`].
    Metadata {
        /// Track title (DMAP `minm`).
        title: Option<String>,
        /// Track artist (DAAP `asar`).
        artist: Option<String>,
        /// Track album (DAAP `asal`).
        album: Option<String>,
    },
    /// `SET_PARAMETER` cover art, exactly as sent (typically `image/jpeg`
    /// or `image/png`, tens to hundreds of KB). Empty `data` — the
    /// `image/none` content type — means the sender cleared the artwork.
    /// Delivered only between [`Event::SessionStarted`] and
    /// [`Event::SessionEnded`].
    Artwork {
        /// The image media type as sent, e.g. `image/jpeg` or `image/png`
        /// (`image/none` accompanies a clear).
        content_type: String,
        /// The image bytes, exactly as sent; empty means cleared.
        data: Vec<u8>,
    },
    /// `SETRATEANCHORTIME` rate gate engaged (`true`) or released. The
    /// library already gates audio delivery itself.
    Paused(bool),
    /// `FLUSHBUFFERED` (seek/skip). The library already dropped its queue
    /// and called [`crate::sink::AudioSink::flush`].
    Flushed,
    /// `TEARDOWN`, or the control connection closed.
    SessionEnded,
}

/// The sending half handed to the library; the host keeps the receiver.
pub type EventSender = tokio::sync::mpsc::UnboundedSender<Event>;