Subscriber as primary (#8)

* Update protos

* Signal client

* Improve transport

* First implementation

* Fix publish

* Update `PCTransport` for debounce negotiation

* debounce func

* reconnect & events

* Update debounce func

* engine events

* make sure events don't emit after dispose

* prefix flutter_webrtc

* Cleaner `iceServers` update

* don't mutate user provided params

* fix tests

* event manager

* Fix: `Room.onDisconnected` gets fired multiple times

* data publish in example

* cleaner logic

* safer events

* un-prefix with LK

* organize imports

* Clean up

* remove `Tuple`

* `EventsEmitter` can now be directly listened to

`EventsEmitter` extends `EventsListenable`

lib/src/proto/livekit_rtc.pbjson.dart

@@ -304,12 +304,13 @@ const JoinResponse$json = const {
       '6': '.livekit.ICEServer',
       '10': 'iceServers'
     },
+    const {'1': 'subscriber_primary', '3': 6, '4': 1, '5': 8, '10': 'subscriberPrimary'},
   ],
 };
 
 /// Descriptor for `JoinResponse`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List joinResponseDescriptor = $convert.base64Decode(
-    'CgxKb2luUmVzcG9uc2USIQoEcm9vbRgBIAEoCzINLmxpdmVraXQuUm9vbVIEcm9vbRI6CgtwYXJ0aWNpcGFudBgCIAEoCzIYLmxpdmVraXQuUGFydGljaXBhbnRJbmZvUgtwYXJ0aWNpcGFudBJHChJvdGhlcl9wYXJ0aWNpcGFudHMYAyADKAsyGC5saXZla2l0LlBhcnRpY2lwYW50SW5mb1IRb3RoZXJQYXJ0aWNpcGFudHMSJQoOc2VydmVyX3ZlcnNpb24YBCABKAlSDXNlcnZlclZlcnNpb24SMwoLaWNlX3NlcnZlcnMYBSADKAsyEi5saXZla2l0LklDRVNlcnZlclIKaWNlU2VydmVycw==');
+    'CgxKb2luUmVzcG9uc2USIQoEcm9vbRgBIAEoCzINLmxpdmVraXQuUm9vbVIEcm9vbRI6CgtwYXJ0aWNpcGFudBgCIAEoCzIYLmxpdmVraXQuUGFydGljaXBhbnRJbmZvUgtwYXJ0aWNpcGFudBJHChJvdGhlcl9wYXJ0aWNpcGFudHMYAyADKAsyGC5saXZla2l0LlBhcnRpY2lwYW50SW5mb1IRb3RoZXJQYXJ0aWNpcGFudHMSJQoOc2VydmVyX3ZlcnNpb24YBCABKAlSDXNlcnZlclZlcnNpb24SMwoLaWNlX3NlcnZlcnMYBSADKAsyEi5saXZla2l0LklDRVNlcnZlclIKaWNlU2VydmVycxItChJzdWJzY3JpYmVyX3ByaW1hcnkYBiABKAhSEXN1YnNjcmliZXJQcmltYXJ5');
 @$core.Deprecated('Use trackPublishedResponseDescriptor instead')
 const TrackPublishedResponse$json = const {
   '1': 'TrackPublishedResponse',