Added Fetch method that accepts refspecs.

To GitClient.

Author: grokys

src/GitHub.App/Services/GitClient.cs

@@ -51,6 +51,18 @@ public IObservable<Unit> Fetch(IRepository repository, string remoteName)
             });
         }
 
+        public IObservable<Unit> Fetch(IRepository repository, string remoteName, params string[] refspecs)
+        {
+            Guard.ArgumentNotEmptyString(remoteName, nameof(remoteName));
+
+            return Observable.Defer(() =>
+            {
+                var remote = repository.Network.Remotes[remoteName];
+                repository.Network.Fetch(remote, refspecs, fetchOptions);
+                return Observable.Return(Unit.Default);
+            });
+        }
+
         public IObservable<Unit> SetRemote(IRepository repository, string remoteName, Uri url)
         {
             Guard.ArgumentNotEmptyString(remoteName, nameof(remoteName));

src/GitHub.Exports.Reactive/Services/IGitClient.cs

@@ -23,6 +23,15 @@ public interface IGitClient
         /// <returns></returns>
         IObservable<Unit> Fetch(IRepository repository, string remoteName);
 
+        /// <summary>
+        /// Fetches from the remote, using custom refspecs.
+        /// </summary>
+        /// <param name="repository">The repository to pull</param>
+        /// <param name="remoteName">The name of the remote</param>
+        /// <param name="refspecs">The custom refspecs</param>
+        /// <returns></returns>
+        IObservable<Unit> Fetch(IRepository repository, string remoteName, params string[] refspecs);
+
         /// <summary>
         /// Sets the specified remote to the specified URL.
         /// </summary>