implement ChatsService and expanded Chat models

Services/ChatMethods.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Chtn.CSharp.SDK.Core;
+using Chtn.CSharp.SDK.Models.Chat;
+
+namespace Chtn.CSharp.SDK.Services
+{
+    public interface IChatsService
+    {
+        Task<List<Chat>> Get(GetChatsReq req);
+        Task<GetAvailabilityResp> GetUserAvailability(GetAvailabilityReq req);
+        Task ToggleMute(ToggleChatMuteReq req);
+        Task<Chat> StartNew(StartNewReq req);
+    }
+
+    public class ChatsServiceProvider : IChatsService
+    {
+        private readonly ApiClient _apiClient;
+
+        public ChatsServiceProvider(ApiClient apiClient)
+        {
+            _apiClient = apiClient ?? throw new ArgumentNullException(nameof(apiClient));
+        }
+
+        public async Task<List<Chat>> Get(GetChatsReq req) =>
+            await _apiClient.PostAsync<GetChatsReq, List<Chat>>("chat/get", req);
+
+        public async Task<GetAvailabilityResp> GetUserAvailability(GetAvailabilityReq req) =>
+            await _apiClient.PostAsync<GetAvailabilityReq, GetAvailabilityResp>("chat/availability", req);
+
+        public async Task ToggleMute(ToggleChatMuteReq req) =>
+            await _apiClient.PostAsync<ToggleChatMuteReq, object>("v2/chat/toggleMute", req);
+
+        public async Task<Chat> StartNew(StartNewReq req) =>
+            await _apiClient.PostAsync<StartNewReq, Chat>("chat/startNew", req);
+    }
+}