code: function getTransactionString(transaction) {
      var result = [];
      for (var key in transaction) {
          if (transaction[key] == null) {
              continue;
          }
          var value = bytes_1.hexlify(transaction[key]);
          if ({ gasLimit: true, gasPrice: true, nonce: true, value: true }[key]) {
              value = bytes_1.hexStripZeros(value);
          }
          result.push(key + '=' + value);
      }
      return result.join('&');
  }
docs: ///////////////////////////// The transaction has already been sanitized by the calls in Provider