public static void onErrorDropped(Throwable e,Throwable root){
  if (root != null) {
    e.addSuppressed(root);
  }
  onErrorDropped(e);
}

public static void onErrorDropped ( Throwable e , Throwable root ) { if ( root != null ) { e . addSuppressed ( root ) ; } onErrorDropped ( e ) ; }
take an unsignalled exception that is masking anowher one due to callback failure .
