docs: private synchronized void initCopy(CopyOperationImpl op) throws SQLException, IOException {
      pgStream.receiveInteger4(); // length not used
      int rowFormat = pgStream.receiveChar();
      int numFields = pgStream.receiveInteger2();
      int[] fieldFormats = new int[numFields];
  
      for (int i = 0; i < numFields; i++) {
        fieldFormats[i] = pgStream.receiveInteger2();
      }
  
      lock(op);
      op.init(this, rowFormat, fieldFormats);
    }