Add possibility to configure GitHubClient timeout (#963)

A first attempt to fix the problem describe in #963 by adding a possibility
to extend the default timeout value (100s)
that is too short to be able to post assets in github release.

Octokit/GitHubClient.cs

@@ -99,6 +99,19 @@ public GitHubClient(IConnection connection)
             Reaction = new ReactionsClient(apiConnection);
         }
 
+        /// <summary>
+        /// Set the GitHub Api request timeout.
+        /// Useful to set a specific timeout for lengthy operations, such as uploading release assets
+        /// </summary>
+        /// <remarks>
+        /// See more information here: https://technet.microsoft.com/library/system.net.http.httpclient.timeout(v=vs.110).aspx
+        /// </remarks>
+        /// <param name="timeout">The Timeout value</param>
+        void SetRequestsTimeout(TimeSpan timeout)
+        {
+            Connection.SetRequestsTimeout(timeout);
+        }
+
         /// <summary>
         /// Gets the latest API Info - this will be null if no API calls have been made
         /// </summary>

Octokit/Http/Connection.cs

@@ -752,5 +752,14 @@ static string GetVersionInformation()
 
             return _versionInformation;
         }
+
+        /// <summary>
+        /// Set the timespan to wait before the requests to GitHub api times out.
+        /// </summary>
+        /// <param name="timeout">the timespan to wait before a request to GitHub api times out</param>
+        public void SetRequestsTimeout(TimeSpan timeout)
+        {
+            _httpClient.SetRequestsTimeout(timeout);
+        }
     }
 }

Octokit/Http/HttpClientAdapter.cs

@@ -264,6 +264,11 @@ public static async Task<HttpRequestMessage> CloneHttpRequestMessageAsync(HttpRe
 
             return newRequest;
         }
+
+        public void SetRequestsTimeout(TimeSpan timeout)
+        {
+            _http.Timeout = timeout;
+        }
     }
 
     internal class RedirectHandler : DelegatingHandler

Octokit/Http/IConnection.cs

@@ -292,5 +292,11 @@ public interface IConnection : IApiInfoProvider
         /// the default <see cref="InMemoryCredentialStore"/> with just these credentials.
         /// </remarks>
         Credentials Credentials { get; set; }
+
+        /// <summary>
+        /// Set the timespan to wait before the requests to GitHub api times out.
+        /// </summary>
+        /// <param name="timeout">the timespan to wait before a request to GitHub api times out</param>
+        void SetRequestsTimeout(TimeSpan timeout);
     }
 }

Octokit/Http/IHttpClient.cs

@@ -19,5 +19,12 @@ public interface IHttpClient : IDisposable
         /// <param name="cancellationToken">Used to cancel the request</param>
         /// <returns>A <see cref="Task" /> of <see cref="IResponse"/></returns>
         Task<IResponse> Send(IRequest request, CancellationToken cancellationToken);
+
+
+        /// <summary>
+        /// Set the timespan to wait before the requests to GitHub api times out.
+        /// </summary>
+        /// <param name="timeout">the timespan to wait before a request to GitHub api times out</param>
+        void SetRequestsTimeout(TimeSpan timeout);
     }
 }