address review comments

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

@@ -334,7 +334,7 @@ namespace Grpc.Core.Internal
         /// </summary>
         protected void HandleReadFinished(bool success, IBufferReader receivedMessageReader)
         {
-            // if success == false, received message will be null. It that case we will
+            // if success == false, the message reader will report null payload. It that case we will
             // treat this completion as the last read an rely on C core to handle the failed
             // read (e.g. deliver approriate statusCode on the clientside).
 

src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs

@@ -113,20 +113,6 @@ namespace Grpc.Core.Internal
             return data;
         }
 
-        public bool GetReceivedMessageNextSlicePeek(out Slice slice)
-        {
-            UIntPtr sliceLen;
-            IntPtr sliceDataPtr;
-            
-            if (0 == Native.grpcsharp_batch_context_recv_message_next_slice_peek(this, out sliceLen, out sliceDataPtr))
-            {
-                slice = default(Slice);
-                return false;
-            }
-            slice = new Slice(sliceDataPtr, (int) sliceLen);
-            return true;
-        }
-
         public IBufferReader GetReceivedMessageReader()
         {
             return this;
@@ -190,7 +176,16 @@ namespace Grpc.Core.Internal
 
         bool IBufferReader.TryGetNextSlice(out Slice slice)
         {
-            return GetReceivedMessageNextSlicePeek(out slice);
+            UIntPtr sliceLen;
+            IntPtr sliceDataPtr;
+
+            if (0 == Native.grpcsharp_batch_context_recv_message_next_slice_peek(this, out sliceLen, out sliceDataPtr))
+            {
+                slice = default(Slice);
+                return false;
+            }
+            slice = new Slice(sliceDataPtr, (int) sliceLen);
+            return true;
         }
 
         struct CompletionCallbackData

src/csharp/Grpc.Core/Internal/ReusableSliceBuffer.cs

@@ -31,36 +31,35 @@ namespace Grpc.Core.Internal
         public const int MaxCachedSegments = 1024;  // ~4MB payload for 4K slices
 
         readonly SliceSegment[] cachedSegments = new SliceSegment[MaxCachedSegments];
-        int populatedSegmentCount = 0;
+        int populatedSegmentCount;
 
         public ReadOnlySequence<byte> PopulateFrom(IBufferReader bufferReader)
         {
+            populatedSegmentCount = 0;
             long offset = 0;
-            int index = 0;
             SliceSegment prevSegment = null;
             while (bufferReader.TryGetNextSlice(out Slice slice))
             {
                 // Initialize cached segment if still null or just allocate a new segment if we already reached MaxCachedSegments
-                var current = index < cachedSegments.Length ? cachedSegments[index] : new SliceSegment();
+                var current = populatedSegmentCount < cachedSegments.Length ? cachedSegments[populatedSegmentCount] : new SliceSegment();
                 if (current == null)
                 {
-                    current = cachedSegments[index] = new SliceSegment();
+                    current = cachedSegments[populatedSegmentCount] = new SliceSegment();
                 }
 
                 current.Reset(slice, offset);
                 prevSegment?.SetNext(current);
 
-                index ++;
+                populatedSegmentCount ++;
                 offset += slice.Length;
                 prevSegment = current;
             }
-            populatedSegmentCount = index;
 
             // Not necessary for ending the ReadOnlySequence, but for making sure we
             // don't keep more than MaxCachedSegments alive.
             prevSegment?.SetNext(null);
 
-            if (index == 0)
+            if (populatedSegmentCount == 0)
             {
                 return ReadOnlySequence<byte>.Empty;
             }
@@ -80,8 +79,9 @@ namespace Grpc.Core.Internal
             while (segment != null)
             {
                 segment.Reset(new Slice(IntPtr.Zero, 0), 0);
+                var nextSegment = (SliceSegment) segment.Next;
                 segment.SetNext(null);
-                segment = (SliceSegment) segment.Next;
+                segment = nextSegment;
             }
             populatedSegmentCount = 0;
         }