Use InputStream#transferTo instead of readAllBytes (opensearch-projec…

…t#6477)

InputStream#transferTo has been available since Java 9 and provides a
built in method to drain an InputStream to an OutputStream without
requiring loading the entire contents of the stream into memory.

Signed-off-by: Andrew Ross <[email protected]>

server/src/main/java/org/opensearch/index/store/remote/utils/TransferManager.java

@@ -107,7 +107,7 @@ private IndexInput downloadBlockLocally(BlobFetchRequest blobFetchRequest) throw
             OutputStream fileOutputStream = Files.newOutputStream(blobFetchRequest.getFilePath());
             OutputStream localFileOutputStream = new BufferedOutputStream(fileOutputStream);
         ) {
-            localFileOutputStream.write(snapshotFileInputStream.readAllBytes());
+            snapshotFileInputStream.transferTo(localFileOutputStream);
         }
         return blobFetchRequest.getDirectory().openInput(blobFetchRequest.getFileName(), IOContext.READ);
     }