diff --git a/Documentation/docfx.json b/Documentation/docfx.json
index 2bcea65..fbd557b 100644
--- a/Documentation/docfx.json
+++ b/Documentation/docfx.json
@@ -11,7 +11,7 @@
       ],
       "dest": "api",
       "filter": "filterConfig.yml",
-      "includePrivateMembers": true,
+      "includePrivateMembers": false,
       "allowCompilationErrors": true
     }
   ],
diff --git a/Documentation/index.md b/Documentation/index.md
index 2b30a41..77d4a87 100644
--- a/Documentation/index.md
+++ b/Documentation/index.md
@@ -11,7 +11,7 @@ A Unity C# wrapper for the Google Cloud Text-To-Speech API.
 
 ## Installation
 
-This *should* work on any reasonably modern Unity version. Built and tested in Unity 6.0.
+Requires Unity 6.0 because of the plugin's usage of [*Awaitable*](https://docs.unity3d.com/6000.0/Documentation/ScriptReference/Awaitable.html). Built and tested in Unity 6.0.
 
 # [OpenUPM](#tab/openupm)
 
diff --git a/README.md b/README.md
index 1cafe10..730c95e 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ A Unity C# wrapper for the Google Cloud Text-To-Speech API.
 
 ## Installation
 
-This *should* work on any reasonably modern Unity version. Built and tested in Unity 6.0.
+Requires Unity 6.0 because of the plugin's usage of [*Awaitable*](https://docs.unity3d.com/6000.0/Documentation/ScriptReference/Awaitable.html). Built and tested in Unity 6.0.
 
 ### OpenUPM
 
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/APIReferenceManual.pdf b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/APIReferenceManual.pdf
index 2698f9a..69e14ef 100644
Binary files a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/APIReferenceManual.pdf and b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/APIReferenceManual.pdf differ
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/Documentation.pdf b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/Documentation.pdf
index c5ec121..126c89a 100644
Binary files a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/Documentation.pdf and b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Documentation~/Documentation.pdf differ
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Synthesis/Response/TextToSpeechSynthesisResponse.cs b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Synthesis/Response/TextToSpeechSynthesisResponse.cs
index 1b7d1ee..3626575 100644
--- a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Synthesis/Response/TextToSpeechSynthesisResponse.cs
+++ b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Synthesis/Response/TextToSpeechSynthesisResponse.cs
@@ -1,7 +1,6 @@
 using Newtonsoft.Json;
 using System;
 using System.IO;
-using System.Threading.Tasks;
 using UnityEngine;
 using UnityEngine.Networking;
 
@@ -39,8 +38,9 @@ public class TextToSpeechSynthesisResponse
         /// <param name="encoding">The encoding of the audio.</param>
         /// <returns>The audio converted to an <see cref="AudioClip"/>.</returns>
         /// <exception cref="IOException">Thrown if <paramref name="encoding"/> is unsupported.</exception>
-        public async Task<AudioClip> ToAudioClip(TextToSpeechSynthesisAudioEncoding encoding)
+        public async Awaitable<AudioClip> ToAudioClip(TextToSpeechSynthesisAudioEncoding encoding)
         {
+            await Awaitable.MainThreadAsync();
             AudioType audioType = encoding switch
             {
                 TextToSpeechSynthesisAudioEncoding.WavLinear16 => AudioType.WAV,
@@ -50,7 +50,7 @@ public async Task<AudioClip> ToAudioClip(TextToSpeechSynthesisAudioEncoding enco
 
             string path = Path.Combine(Application.temporaryCachePath, $"{nameof(TextToSpeechSynthesisResponse)}.bin");
             byte[] buffer = Convert.FromBase64String(Audio);
-            File.WriteAllBytes(path, buffer);
+            await File.WriteAllBytesAsync(path, buffer);
 
             using UnityWebRequest audioClipRequest = UnityWebRequestMultimedia.GetAudioClip($"file://{path}", audioType);
             await audioClipRequest.SendWebRequest();
@@ -65,7 +65,7 @@ public async Task<AudioClip> ToAudioClip(TextToSpeechSynthesisAudioEncoding enco
         /// </summary>
         /// <returns>The audio converted to an <see cref="AudioClip"/>.</returns>
         /// <exception cref="IOException">Thrown if <paramref name="encoding"/> is unsupported.</exception>
-        public async Task<AudioClip> ToAudioClip()
+        public async Awaitable<AudioClip> ToAudioClip()
         {
             return await ToAudioClip(AudioMetadata?.Encoding ?? TextToSpeechSynthesisAudioEncoding.Default);
         }
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/TextToSpeechVoiceType.cs b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/TextToSpeechVoiceType.cs
index d9491ae..61028f3 100644
--- a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/TextToSpeechVoiceType.cs
+++ b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/TextToSpeechVoiceType.cs
@@ -5,6 +5,11 @@
     /// </summary>
     public enum TextToSpeechVoiceType
     {
+        /// <summary>
+        /// Default value, ignore.
+        /// </summary>
+        None,
+
         /// <summary>
         /// <seealso href="https://cloud.google.com/text-to-speech/docs/voice-types#standard_voices">Standard</seealso>
         /// </summary>
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Voices/IEnumerableExtensions.cs b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Voices/IEnumerableExtensions.cs
index 8f2f77c..8276349 100644
--- a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Voices/IEnumerableExtensions.cs
+++ b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Data/Voices/IEnumerableExtensions.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -16,7 +17,7 @@ public static class IEnumerableExtensions
         /// <returns>Voices with the type and gender corresponding to <paramref name="type"/> and <paramref name="gender"/>.</returns>
         public static IEnumerable<TextToSpeechVoice> FilterByAttributes(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceGender gender, TextToSpeechVoiceType type)
         {
-            return from voice in thiz where voice.Gender == gender && voice.Name.Type == type select voice;
+            return from voice in thiz where voice?.Gender == gender && voice?.Name?.Type == type select voice;
         }
 
         /// <summary>
@@ -26,7 +27,7 @@ public static IEnumerable<TextToSpeechVoice> FilterByAttributes(this IEnumerable
         /// <returns>Voices with the gender corresponding to <paramref name="gender"/>.</returns>
         public static IEnumerable<TextToSpeechVoice> FilterByGender(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceGender gender)
         {
-            return from voice in thiz where voice.Gender == gender select voice;
+            return from voice in thiz where voice?.Gender == gender select voice;
         }
 
         /// <summary>
@@ -36,7 +37,7 @@ public static IEnumerable<TextToSpeechVoice> FilterByGender(this IEnumerable<Tex
         /// <returns>Voices with the type corresponding to <paramref name="type"/>.</returns>
         public static IEnumerable<TextToSpeechVoice> FilterByType(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceType type)
         {
-            return from voice in thiz where voice.Name.Type == type select voice;
+            return from voice in thiz where voice?.Name?.Type == type select voice;
         }
 
         /// <summary>
@@ -47,7 +48,42 @@ public static IEnumerable<TextToSpeechVoice> FilterByType(this IEnumerable<TextT
         /// <returns>A voice with the type and gender corresponding to <paramref name="type"/> and <paramref name="gender"/>, <see langword="null"/> if not found.</returns>
         public static TextToSpeechVoice FindByAttributes(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceGender gender, TextToSpeechVoiceType type)
         {
-            return thiz.FirstOrDefault(voice => voice.Gender == gender && voice.Name.Type == type);
+            return thiz.FirstOrDefault(voice => voice?.Gender == gender && voice?.Name?.Type == type);
+        }
+
+        /// <summary>
+        /// Finds the first voice with the given <paramref name="gender"/> and one of the specified <paramref name="types"/>,
+        /// where the order of types in <paramref name="types"/> specifies preference. 
+        /// </summary>
+        /// <remarks>
+        /// The method searches the collection and returns the first voice that matches the gender and any of the provided types, 
+        /// preferring the order in which the types are listed.
+        /// </remarks>
+        /// <param name="thiz">The collection of voices to search within.</param>
+        /// <param name="gender">The gender to filter by.</param>
+        /// <param name="types">The types to filter by. Order indicates preference.</param>
+        /// <returns>The first voice matching the gender and one of the specified types, or null if none is found.</returns>
+        public static TextToSpeechVoice FindByAttributes(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceGender gender, params TextToSpeechVoiceType[] types)
+        {
+            if (types.Length < 2)
+                return types.Length == 0 ? FindByGender(thiz, gender) : FindByAttributes(thiz, gender, types[0]);
+            
+            Dictionary<TextToSpeechVoiceType, TextToSpeechVoice> foundVoices = new(types.Length);
+            foreach (TextToSpeechVoice voice in thiz)
+            {
+                if (voice?.Gender != gender)
+                    continue;
+
+                TextToSpeechVoiceType type = voice.Name.Type;
+                int index = Array.IndexOf(types, type);
+
+                if (index == 0)
+                    return voice;
+                else if (index >= 0 && !foundVoices.ContainsKey(type))
+                    foundVoices[type] = voice;
+            }
+
+            return (from type in types where foundVoices.ContainsKey(type) select foundVoices[type]).FirstOrDefault();
         }
 
         /// <summary>
@@ -57,7 +93,7 @@ public static TextToSpeechVoice FindByAttributes(this IEnumerable<TextToSpeechVo
         /// <returns>A voice with the gender corresponding to <paramref name="gender"/>, <see langword="null"/> if not found.</returns>
         public static TextToSpeechVoice FindByGender(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceGender gender)
         {
-            return thiz.FirstOrDefault(voice => voice.Gender == gender);
+            return thiz.FirstOrDefault(voice => voice?.Gender == gender);
         }
 
         /// <summary>
@@ -67,7 +103,7 @@ public static TextToSpeechVoice FindByGender(this IEnumerable<TextToSpeechVoice>
         /// <returns>A voice with the type corresponding to <paramref name="type"/>, <see langword="null"/> if not found.</returns>
         public static TextToSpeechVoice FindByType(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceType type)
         {
-            return thiz.FirstOrDefault(voice => voice.Name.Type == type);
+            return thiz.FirstOrDefault(voice => voice?.Name?.Type == type);
         }
 
         /// <summary>
@@ -77,8 +113,8 @@ public static TextToSpeechVoice FindByType(this IEnumerable<TextToSpeechVoice> t
         /// <returns>A voice with the name corresponding to <paramref name="name"/>, <see langword="null"/> if not found.</returns>
         public static TextToSpeechVoice FindByName(this IEnumerable<TextToSpeechVoice> thiz, TextToSpeechVoiceName name)
         {
-            string nameStr = name.FullName;
-            return thiz.FirstOrDefault(voice => voice.Name.FullName == nameStr);
+            string nameStr = name?.FullName;
+            return thiz.FirstOrDefault(voice => voice?.Name?.FullName == nameStr);
         }
     }
 }
\ No newline at end of file
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Managers/TextToSpeechManager.cs b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Managers/TextToSpeechManager.cs
index 0bc72ac..49622c0 100644
--- a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Managers/TextToSpeechManager.cs
+++ b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/Runtime/Scripts/Managers/TextToSpeechManager.cs
@@ -1,6 +1,5 @@
 using Newtonsoft.Json;
 using System;
-using System.Threading.Tasks;
 using UnityEngine;
 using UnityEngine.Networking;
 using Uralstech.UCloud.TextToSpeech.Exceptions;
@@ -58,8 +57,9 @@ public void SetApiKey(string apiKey)
         /// <returns>The computed response.</returns>
         /// <exception cref="TextToSpeechRequestException">Thrown if the API request fails.</exception>
         /// <exception cref="TextToSpeechResponseParsingException">Thrown if the response could not be parsed.</exception>
-        public async Task<TResponse> Request<TResponse>(ITextToSpeechPostRequest request)
+        public async Awaitable<TResponse> Request<TResponse>(ITextToSpeechPostRequest request)
         {
+            await Awaitable.MainThreadAsync();
             string utf8RequestData = request.GetUtf8EncodedData();
             string requestEndpoint = request.GetEndpointUri();
 
@@ -85,8 +85,9 @@ public async Task<TResponse> Request<TResponse>(ITextToSpeechPostRequest request
         /// <returns>The computed response.</returns>
         /// <exception cref="TextToSpeechRequestException">Thrown if the API request fails.</exception>
         /// <exception cref="TextToSpeechResponseParsingException">Thrown if the response could not be parsed.</exception>
-        public async Task<TResponse> Request<TResponse>(ITextToSpeechGetRequest request)
+        public async Awaitable<TResponse> Request<TResponse>(ITextToSpeechGetRequest request)
         {
+            await Awaitable.MainThreadAsync();
             string requestEndpoint = request.GetEndpointUri();
 
             using UnityWebRequest webRequest = UnityWebRequest.Get(requestEndpoint);
diff --git a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/package.json b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/package.json
index 6a4eb3d..44318b5 100644
--- a/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/package.json
+++ b/UCloud.TextToSpeech/Packages/com.uralstech.ucloud.texttospeech/package.json
@@ -3,7 +3,7 @@
   "displayName": "UCloud.TextToSpeech",
   "description": "A Unity C# wrapper for the Google Cloud Text-To-Speech API.",
   "keywords": [],
-  "version": "1.1.0",
+  "version": "1.2.0",
   "unity": "6000.0",
   "hideInEditor": false,
   "documentationUrl": "https://uralstech.github.io/UCloud.TextToSpeech/",