code: public void marshall(User user, ProtocolMarshaller protocolMarshaller) {
  
          if (user == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(user.getUserId(), USERID_BINDING);
              protocolMarshaller.marshall(user.getAccountId(), ACCOUNTID_BINDING);
              protocolMarshaller.marshall(user.getPrimaryEmail(), PRIMARYEMAIL_BINDING);
              protocolMarshaller.marshall(user.getPrimaryProvisionedNumber(), PRIMARYPROVISIONEDNUMBER_BINDING);
              protocolMarshaller.marshall(user.getDisplayName(), DISPLAYNAME_BINDING);
              protocolMarshaller.marshall(user.getLicenseType(), LICENSETYPE_BINDING);
              protocolMarshaller.marshall(user.getUserRegistrationStatus(), USERREGISTRATIONSTATUS_BINDING);
              protocolMarshaller.marshall(user.getUserInvitationStatus(), USERINVITATIONSTATUS_BINDING);
              protocolMarshaller.marshall(user.getRegisteredOn(), REGISTEREDON_BINDING);
              protocolMarshaller.marshall(user.getInvitedOn(), INVITEDON_BINDING);
              protocolMarshaller.marshall(user.getPersonalPIN(), PERSONALPIN_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.