Revert "wip"

This reverts commit e109e2c.

Author: xborder

flight/flight-core/src/main/java/org/apache/arrow/flight/ArrowMessage.java

@@ -312,12 +312,8 @@ private static ArrowMessage frame(BufferAllocator allocator, final InputStream s
           case APP_METADATA_TAG:
             {
               int size = readRawVarint32(stream);
-              if (ENABLE_ZERO_COPY_READ) {
-                appMetadata = GetReadableBuffer.readWithOwnershipTransfer(allocator, stream, size);
-              } else {
-                appMetadata = allocator.buffer(size);
-                GetReadableBuffer.readIntoBuffer(stream, appMetadata, size, false);
-              }
+              appMetadata = allocator.buffer(size);
+              GetReadableBuffer.readIntoBuffer(stream, appMetadata, size, ENABLE_ZERO_COPY_READ);
               break;
             }
           case BODY_TAG:
@@ -327,12 +323,8 @@ private static ArrowMessage frame(BufferAllocator allocator, final InputStream s
               body = null;
             }
             int size = readRawVarint32(stream);
-            if (ENABLE_ZERO_COPY_READ) {
-              body = GetReadableBuffer.readWithOwnershipTransfer(allocator, stream, size);
-            } else {
-              body = allocator.buffer(size);
-              GetReadableBuffer.readIntoBuffer(stream, body, size, false);
-            }
+            body = allocator.buffer(size);
+            GetReadableBuffer.readIntoBuffer(stream, body, size, ENABLE_ZERO_COPY_READ);
             break;
 
           default: