Collapse AsSpan().Slice(..) into AsSpan(..) (#1991)

Author: ahsonkhan

src/Common/MemoryBufferWriter.cs

@@ -288,7 +288,7 @@ public override void Write(byte[] buffer, int offset, int count)
 #if NETCOREAPP2_1
         public override void Write(ReadOnlySpan<byte> span)
         {
-            if (_currentSegment != null && span.TryCopyTo(_currentSegment.AsSpan().Slice(_position)))
+            if (_currentSegment != null && span.TryCopyTo(_currentSegment.AsSpan(_position)))
             {
                 _position += span.Length;
                 _bytesWritten += span.Length;

test/Microsoft.AspNetCore.SignalR.Tests/EndToEndTests.cs

@@ -107,7 +107,7 @@ public async Task WebSocketsTest()
                     var result = await ws.ReceiveAsync(buffer, CancellationToken.None).OrTimeout();
                     logger.LogInformation("Received {length} byte frame", result.Count);
 
-                    Assert.Equal(bytes, buffer.Array.AsSpan().Slice(0, result.Count).ToArray());
+                    Assert.Equal(bytes, buffer.Array.AsSpan(0, result.Count).ToArray());
 
                     logger.LogInformation("Closing socket");
                     await ws.CloseOutputAsync(WebSocketCloseStatus.Empty, "", CancellationToken.None).OrTimeout();
@@ -145,7 +145,7 @@ public async Task WebSocketsReceivesAndSendsPartialFramesTest()
                     var result = await ws.ReceiveAsync(buffer, CancellationToken.None).OrTimeout();
                     logger.LogInformation("Received {length} byte frame", result.Count);
 
-                    Assert.Equal(bytes, buffer.Array.AsSpan().Slice(0, result.Count).ToArray());
+                    Assert.Equal(bytes, buffer.Array.AsSpan(0, result.Count).ToArray());
 
                     logger.LogInformation("Closing socket");
                     await ws.CloseOutputAsync(WebSocketCloseStatus.Empty, "", CancellationToken.None).OrTimeout();