Adding WithToken to ISlackApiClient for using a different access token

SlackNet.Tests/ApiLintTest.cs

@@ -180,6 +180,11 @@ public Task Respond(string responseUrl, IReadOnlyMessage message, CancellationTo
                 throw new NotImplementedException();
             }
 
+            public ISlackApiClient WithAccessToken(string accessToken)
+            {
+                throw new NotImplementedException();
+            }
+
             public IApiApi Api { get; }
             public IAuthApi Auth { get; }
             public IBotsApi Bots { get; }

SlackNet/SlackApiClient.cs

@@ -105,6 +105,13 @@ public interface ISlackApiClient
         /// <param name="message">The message to respond with.</param>
         /// <param name="cancellationToken"></param>
         Task Respond(string responseUrl, IReadOnlyMessage message, CancellationToken? cancellationToken);
+
+        /// <summary>
+        /// Returns a copy of the client using a different access token.
+        /// Useful when you need to run a command as a specific user.
+        /// </summary>
+        /// <param name="accessToken">New access token.</param>
+        ISlackApiClient WithAccessToken(string accessToken);
     }
 
     public class SlackApiClient : ISlackApiClient
@@ -130,6 +137,13 @@ public SlackApiClient(IHttp http, ISlackUrlBuilder urlBuilder, SlackJsonSettings
             _token = token;
         }
 
+        /// <summary>
+        /// Returns a copy of the client using a different access token.
+        /// Useful when you need to run a command as a specific user.
+        /// </summary>
+        /// <param name="accessToken">New access token.</param>
+        public ISlackApiClient WithAccessToken(string accessToken) => new SlackApiClient(_http, _urlBuilder, _jsonSettings, accessToken);
+
         public IApiApi Api => new ApiApi(this);
         public IAuthApi Auth => new AuthApi(this);
         public IBotsApi Bots => new BotsApi(this);