fix usages of ReleaseBufferToPool

Author: mythz

src/ServiceStack.Text/DefaultMemory.cs

@@ -460,23 +460,31 @@ public override void Write(Stream stream, ReadOnlyMemory<byte> value)
 
         public override Task WriteAsync(Stream stream, ReadOnlySpan<char> value, CancellationToken token = default)
         {
+            // encode the span into a buffer; this should never fail, so if it does: something
+            // is very very ill; don't stress about returning to the pool
             byte[] bytes = BufferPool.GetBuffer(Encoding.UTF8.GetMaxByteCount(value.Length));
+            var chars = value.ToArray();
+            int bytesCount = Encoding.UTF8.GetBytes(chars, 0, chars.Length, bytes, 0);
+            // now do the write async - this returns to the pool
+            return WriteAsyncAndReturn(stream, bytes, 0, bytesCount, token);
+        }
+        
+        private static async Task WriteAsyncAndReturn(Stream stream, byte[] bytes, int offset, int count, CancellationToken token)
+        {
             try
             {
-                var chars = value.ToArray();
-                int bytesCount = Encoding.UTF8.GetBytes(chars, 0, chars.Length, bytes, 0);
-                return stream.WriteAsync(bytes, 0, bytesCount, token);
+                await stream.WriteAsync(bytes, offset, count, token);
             }
             finally
             {
                 BufferPool.ReleaseBufferToPool(ref bytes);
             }
         }
-
+        
         public override Task WriteAsync(Stream stream, ReadOnlyMemory<char> value, CancellationToken token = default) =>
             WriteAsync(stream, value.Span, token);
 
-        public override Task WriteAsync(Stream stream, ReadOnlyMemory<byte> value, CancellationToken token = default)
+        public override async Task WriteAsync(Stream stream, ReadOnlyMemory<byte> value, CancellationToken token = default)
         {
             byte[] bytes = BufferPool.GetBuffer(value.Length);
             try
@@ -485,11 +493,10 @@ public override Task WriteAsync(Stream stream, ReadOnlyMemory<byte> value, Cance
                 if (stream is MemoryStream ms)
                 {
                     ms.Write(bytes, 0, value.Length);
-                    return TypeConstants.EmptyTask;
                 }
                 else
                 {
-                    return stream.WriteAsync(bytes, 0, value.Length, token);
+                    await stream.WriteAsync(bytes, 0, value.Length, token);
                 }
             }
             finally