question: @ Nullable public static List < Byte > readByteList ( DataInput in ) throws IOException { int size = in . readInt ( ) ; if ( size == - 1 ) return null ; List < Byte > col = new ArrayList < > ( size ) ; for ( int i = 0 ; i < size ; i ++ ) col . add ( in . readByte ( ) ) ; return col ; }
target:  // FIXME: added for DR dataCenterIds, review if it is needed after GG-6879.