always include plugin info & user data when serializing (lavalink-devs#1008)

Author: topi314

protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/loadResult.kt

@@ -3,10 +3,7 @@
 package dev.arbjerg.lavalink.protocol.v4
 
 import dev.arbjerg.lavalink.protocol.v4.serialization.asPolymorphicDeserializer
-import kotlinx.serialization.DeserializationStrategy
-import kotlinx.serialization.KSerializer
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
+import kotlinx.serialization.*
 import kotlinx.serialization.builtins.ListSerializer
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
@@ -133,6 +130,7 @@ data class PlaylistInfo(
 @Serializable
 data class Playlist(
     val info: PlaylistInfo,
+    @EncodeDefault
     val pluginInfo: JsonObject = JsonObject(emptyMap()),
     val tracks: List<Track>
 ) : LoadResult.Data {

protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/player.kt

@@ -1,9 +1,8 @@
 package dev.arbjerg.lavalink.protocol.v4
 
-import kotlinx.serialization.DeserializationStrategy
-import kotlinx.serialization.Serializable
+import kotlinx.serialization.*
+import kotlinx.serialization.json.JsonNames
 import kotlinx.serialization.json.JsonObject
-import kotlinx.serialization.serializer
 import kotlin.jvm.JvmInline
 
 inline fun <reified T> JsonObject.deserialize(): T =
@@ -31,7 +30,9 @@ data class Player(
 data class Track(
     val encoded: String,
     val info: TrackInfo,
+    @EncodeDefault
     val pluginInfo: JsonObject = JsonObject(emptyMap()),
+    @EncodeDefault
     val userData: JsonObject = JsonObject(emptyMap())
 ) : LoadResult.Data {