code: func (api *API) ReplayBundle(tailTxHash Hash, depth uint64, mwm uint64, reference ...Hash) (bundle.Bundle, error) {
  	if err := Validate(ValidateTransactionHashes(tailTxHash)); err != nil {
  		return nil, err
  	}
  	bndl, err := api.GetBundle(tailTxHash)
  	if err != nil {
  		return nil, err
  	}
  	trytes := transaction.MustFinalTransactionTrytes(bndl)
  	return api.SendTrytes(trytes, depth, mwm, reference...)
  }
docs: // ReplayBundle reattaches a transfer to the Tangle by selecting tips & performing the Proof-of-Work again.
  // Reattachments are useful in case original transactions are pending and can be done securely
  // as many times as needed.