Add option to enable audio preconnect buffer in SDK & FFI (#700)

* add preconnect buffer option to ffi room proto

* set AudioTrackFeatures on AddTrackRequest

* add preconect to conversion from proto to TrackPublishOptions

Author: chenosaurus

livekit-ffi/protocol/room.proto

@@ -261,6 +261,7 @@ message TrackPublishOptions {
   optional bool simulcast = 6;
   optional TrackSource source = 7;
   optional string stream = 8;
+  optional bool preconnect_buffer = 9;
 }
 
 enum IceTransportType {

livekit-ffi/src/conversion/room.rs

@@ -232,6 +232,9 @@ impl From<proto::TrackPublishOptions> for TrackPublishOptions {
             red: opts.red.unwrap_or(default_publish_options.red),
             simulcast: opts.simulcast.unwrap_or(default_publish_options.simulcast),
             stream: opts.stream.unwrap_or(default_publish_options.stream),
+            preconnect_buffer: opts
+                .preconnect_buffer
+                .unwrap_or(default_publish_options.preconnect_buffer),
         }
     }
 }

livekit-ffi/src/livekit.proto.rs

@@ -3256,6 +3256,8 @@ pub struct TrackPublishOptions {
     pub source: ::core::option::Option<i32>,
     #[prost(string, optional, tag="8")]
     pub stream: ::core::option::Option<::prost::alloc::string::String>,
+    #[prost(bool, optional, tag="9")]
+    pub preconnect_buffer: ::core::option::Option<bool>,
 }
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]

livekit/src/room/options.rs

@@ -85,6 +85,7 @@ pub struct TrackPublishOptions {
     // pub name: String,
     pub source: TrackSource,
     pub stream: String,
+    pub preconnect_buffer: bool,
 }
 
 impl Default for TrackPublishOptions {
@@ -98,6 +99,7 @@ impl Default for TrackPublishOptions {
             simulcast: true,
             source: TrackSource::Unknown,
             stream: "".to_string(),
+            preconnect_buffer: false,
         }
     }
 }

livekit/src/room/participant/local_participant.rs

@@ -245,6 +245,10 @@ impl LocalParticipant {
             ..Default::default()
         };
 
+        if options.preconnect_buffer {
+            req.audio_features.push(proto::AudioTrackFeature::TfPreconnectBuffer as i32);
+        }
+
         let mut encodings = Vec::default();
         match &track {
             LocalTrack::Video(video_track) => {