Merge pull request #20775 from davkean/RemoveAllocation

Remove capture allocation from WriteArray

Author: davkean

src/Compilers/Core/Portable/Serialization/ObjectWriter.cs

@@ -484,7 +484,8 @@ private void WriteArray(Array array)
                     // don't blow the stack.  'LongRunning' ensures that we get a dedicated thread
                     // to do this work.  That way we don't end up blocking the threadpool.
                     var task = Task.Factory.StartNew(
-                        () => WriteArrayValues(array),
+                        a => WriteArrayValues((Array)a), 
+                        array,
                         _cancellationToken,
                         TaskCreationOptions.LongRunning,
                         TaskScheduler.Default);