Make ResumeSession ResumeSessionAsync

- It calls IClientTransport.ConnectAsync, so it should be async as well

Author: halter73

src/ModelContextProtocol.Core/Client/HttpClientTransportOptions.cs

@@ -84,7 +84,7 @@ public required Uri Endpoint
     /// </para>
     /// <para>
     /// Clients should pair this with
-    /// <see cref="McpClient.ResumeSession(IClientTransport, ResumeClientSessionOptions, McpClientOptions?, Microsoft.Extensions.Logging.ILoggerFactory?, CancellationToken)"/>
+    /// <see cref="McpClient.ResumeSessionAsync(IClientTransport, ResumeClientSessionOptions, McpClientOptions?, Microsoft.Extensions.Logging.ILoggerFactory?, CancellationToken)"/>
     /// to skip the initialization handshake when rehydrating a previously negotiated session.
     /// </para>
     /// </remarks>

src/ModelContextProtocol.Core/Client/McpClient.Methods.cs

@@ -60,7 +60,7 @@ public static async Task<McpClient> CreateAsync(
     /// <param name="cancellationToken">Token used when establishing the transport connection.</param>
     /// <returns>An <see cref="McpClient"/> bound to the resumed session.</returns>
     /// <exception cref="ArgumentNullException">Thrown when <paramref name="clientTransport"/> or <paramref name="resumeOptions"/> is <see langword="null"/>.</exception>
-    public static McpClient ResumeSession(
+    public static async Task<McpClient> ResumeSessionAsync(
         IClientTransport clientTransport,
         ResumeClientSessionOptions resumeOptions,
         McpClientOptions? clientOptions = null,
@@ -72,7 +72,7 @@ public static McpClient ResumeSession(
         Throw.IfNull(resumeOptions.ServerCapabilities);
         Throw.IfNull(resumeOptions.ServerInfo);
 
-        var transport = clientTransport.ConnectAsync(cancellationToken).GetAwaiter().GetResult();
+        var transport = await clientTransport.ConnectAsync(cancellationToken).ConfigureAwait(false);
         var endpointName = clientTransport.Name;
 
         var clientSession = new McpClientImpl(transport, endpointName, clientOptions, loggerFactory);

src/ModelContextProtocol.Core/Client/ResumeClientSessionOptions.cs

@@ -16,6 +16,7 @@ public sealed class ResumeClientSessionOptions
     /// Gets or sets the server implementation metadata that identifies the connected MCP server.
     /// </summary>
     public required Implementation ServerInfo { get; set; }
+
     /// <summary>
     /// Gets or sets any instructions previously supplied by the server.
     /// </summary>

src/ModelContextProtocol.Core/Client/StreamableHttpClientSessionTransport.cs

@@ -71,7 +71,7 @@ internal async Task<HttpResponseMessage> SendHttpRequestAsync(JsonRpcMessage mes
         {
             throw new InvalidOperationException(
                 $"Cannot send '{RequestMethods.Initialize}' when {nameof(HttpClientTransportOptions)}.{nameof(HttpClientTransportOptions.KnownSessionId)} is configured. " +
-                $"Call {nameof(McpClient)}.{nameof(McpClient.ResumeSession)} to resume existing sessions.");
+                $"Call {nameof(McpClient)}.{nameof(McpClient.ResumeSessionAsync)} to resume existing sessions.");
         }
 
         using var sendCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, _connectionCts.Token);

tests/ModelContextProtocol.AspNetCore.Tests/MapMcpStreamableHttpTests.cs

@@ -268,7 +268,7 @@ public async Task CanResumeSessionWithMapMcpAndRunSessionHandler()
             NegotiatedProtocolVersion = negotiatedProtocolVersion,
         };
 
-        await using (var resumedClient = McpClient.ResumeSession(
+        await using (var resumedClient = await McpClient.ResumeSessionAsync(
             resumeTransport,
             resumeOptions,
             loggerFactory: LoggerFactory,

tests/ModelContextProtocol.AspNetCore.Tests/StreamableHttpClientConformanceTests.cs

@@ -239,7 +239,7 @@ public async Task ResumeSessionStartsGetImmediately()
             NegotiatedProtocolVersion = resumeProtocolVersion,
         };
 
-        await using (var client = McpClient.ResumeSession(
+        await using (var client = await McpClient.ResumeSessionAsync(
             transport,
             resumeOptions,
             loggerFactory: LoggerFactory,
@@ -277,7 +277,7 @@ public async Task CreateAsyncWithKnownSessionIdThrows()
         var exception = await Assert.ThrowsAsync<InvalidOperationException>(() =>
             McpClient.CreateAsync(transport, loggerFactory: LoggerFactory, cancellationToken: TestContext.Current.CancellationToken));
 
-        Assert.Contains(nameof(McpClient.ResumeSession), exception.Message);
+        Assert.Contains(nameof(McpClient.ResumeSessionAsync), exception.Message);
     }
 
     private static async Task CallEchoAndValidateAsync(McpClientTool echoTool)