code: public com.google.api.ads.adwords.axis.v201809.rm.OfflineDataUploadUserIdentifierType getUserIdentifierType() {
          return userIdentifierType;
      }
docs: Gets the userIdentifierType value for this UserIdentifier.
  
  @return userIdentifierType   * Type of user identifier.
  <span class="constraint Required">This field is required
  and should not be {@code null}.</span>