audout: Implement and fix some calls (#1725)

* audout: Implement GetAudioOutBufferCount, GetAudioOutPlayedSampleCount and FlushAudioOutBuffers

This PR implement audout service calls:
- GetAudioOutBufferCount
- GetAudioOutPlayedSampleCount
- FlushAudioOutBuffers

The RE calls just give some hints about no extra checks.
Since we use a totally different implementation because of our backend, I can't do something better for now.

SetAudioOutVolume and GetAudioOutVolume are fixed too by set/get the volume of the current opened track, previous implementation was wrong.

This fix #1133, fix #1258 and fix #1519.

Thanks to @jduncanator for this help during the implementation and all his precious advices.

* Fix some debug leftovers

* Address jD feedback

Ryujinx.Audio/Renderers/SoundIo/SoundIoAudioTrack.cs

@@ -54,6 +54,16 @@ namespace Ryujinx.Audio.SoundIo
         /// </summary>
         public ConcurrentQueue<long> ReleasedBuffers { get; private set; }
 
+        /// <summary>
+        /// Buffer count of the track
+        /// </summary>
+        public uint BufferCount => (uint)m_ReservedBuffers.Count;
+
+        /// <summary>
+        /// Played sample count of the track
+        /// </summary>
+        public ulong PlayedSampleCount { get; private set; }
+
         private int _hardwareChannels;
         private int _virtualChannels;
 
@@ -430,6 +440,8 @@ namespace Ryujinx.Audio.SoundIo
 
             AudioStream.EndWrite();
 
+            PlayedSampleCount += (ulong)samples.Length;
+
             UpdateReleasedBuffers(samples.Length);
         }
 
@@ -571,6 +583,28 @@ namespace Ryujinx.Audio.SoundIo
             return m_ReservedBuffers.Any(x => x.Tag == bufferTag);
         }
 
+        /// <summary>
+        /// Flush all track buffers
+        /// </summary>
+        public bool FlushBuffers()
+        {
+            m_Buffer.Clear();
+
+            if (m_ReservedBuffers.Count > 0)
+            {
+                foreach (var buffer in m_ReservedBuffers)
+                {
+                    ReleasedBuffers.Enqueue(buffer.Tag);
+                }
+
+                OnBufferReleased();
+
+                return true;
+            }
+
+            return false;
+        }
+
         /// <summary>
         /// Closes the <see cref="SoundIoAudioTrack"/>
         /// </summary>