Add Backlog to QuicTransportOptions (dotnet#35312)

Author: wtgodbe

src/Servers/Kestrel/Transport.Quic/src/Internal/QuicConnectionListener.cs

@@ -58,6 +58,7 @@ public QuicConnectionListener(QuicTransportOptions options, IQuicTrace log, EndP
             quicListenerOptions.IdleTimeout = options.IdleTimeout;
             quicListenerOptions.MaxBidirectionalStreams = options.MaxBidirectionalStreamCount;
             quicListenerOptions.MaxUnidirectionalStreams = options.MaxUnidirectionalStreamCount;
+            quicListenerOptions.ListenBacklog = options.Backlog;
 
             _listener = new QuicListener(quicListenerOptions);
 

src/Servers/Kestrel/Transport.Quic/src/PublicAPI.Unshipped.txt

@@ -26,6 +26,8 @@
 *REMOVED*~static Microsoft.AspNetCore.Hosting.WebHostBuilderMsQuicExtensions.UseQuic(this Microsoft.AspNetCore.Hosting.IWebHostBuilder hostBuilder) -> Microsoft.AspNetCore.Hosting.IWebHostBuilder
 Microsoft.AspNetCore.Hosting.WebHostBuilderQuicExtensions
 Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions
+Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions.Backlog.get -> int
+Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions.Backlog.set -> void
 Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions.IdleTimeout.get -> System.TimeSpan
 Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions.IdleTimeout.set -> void
 Microsoft.AspNetCore.Server.Kestrel.Transport.Quic.QuicTransportOptions.MaxBidirectionalStreamCount.get -> ushort

src/Servers/Kestrel/Transport.Quic/src/QuicTransportOptions.cs

@@ -40,6 +40,11 @@ public class QuicTransportOptions
         /// </summary>
         public long? MaxWriteBufferSize { get; set; } = 64 * 1024;
 
+        /// <summary>
+        /// The maximum length of the pending connection queue.
+        /// </summary>
+        public int Backlog { get; set; } = 512;
+
         internal ISystemClock SystemClock = new SystemClock();
     }
 }