docs: public void marshall(StartOutboundVoiceContactRequest startOutboundVoiceContactRequest, ProtocolMarshaller protocolMarshaller) {
  
          if (startOutboundVoiceContactRequest == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getDestinationPhoneNumber(), DESTINATIONPHONENUMBER_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getContactFlowId(), CONTACTFLOWID_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getInstanceId(), INSTANCEID_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getClientToken(), CLIENTTOKEN_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getSourcePhoneNumber(), SOURCEPHONENUMBER_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getQueueId(), QUEUEID_BINDING);
              protocolMarshaller.marshall(startOutboundVoiceContactRequest.getAttributes(), ATTRIBUTES_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }