@SdkInternalApi
    final StartCompositionResult executeStartComposition(StartCompositionRequest startCompositionRequest) {

        ExecutionContext executionContext = createExecutionContext(startCompositionRequest);
        AWSRequestMetrics awsRequestMetrics = executionContext.getAwsRequestMetrics();
        awsRequestMetrics.startEvent(Field.ClientExecuteTime);
        Request<StartCompositionRequest> request = null;
        Response<StartCompositionResult> response = null;

        try {
            awsRequestMetrics.startEvent(Field.RequestMarshallTime);
            try {
                request = new StartCompositionRequestProtocolMarshaller(protocolFactory).marshall(super.beforeMarshalling(startCompositionRequest));
                // Binds the request metrics to the current request.
                request.setAWSRequestMetrics(awsRequestMetrics);
                request.addHandlerContext(HandlerContextKey.CLIENT_ENDPOINT, endpoint);
                request.addHandlerContext(HandlerContextKey.ENDPOINT_OVERRIDDEN, isEndpointOverridden());
                request.addHandlerContext(HandlerContextKey.SIGNING_REGION, getSigningRegion());
                request.addHandlerContext(HandlerContextKey.SERVICE_ID, "IVS RealTime");
                request.addHandlerContext(HandlerContextKey.OPERATION_NAME, "StartComposition");
                request.addHandlerContext(HandlerContextKey.ADVANCED_CONFIG, advancedConfig);

            } finally {
                awsRequestMetrics.endEvent(Field.RequestMarshallTime);
            }

            HttpResponseHandler<AmazonWebServiceResponse<StartCompositionResult>> responseHandler = protocolFactory.createResponseHandler(
                    new JsonOperationMetadata().withPayloadJson(true).withHasStreamingSuccessResponse(false), new StartCompositionResultJsonUnmarshaller());
            response = invoke(request, responseHandler, executionContext);

            return response.getAwsResponse();

        } finally {

            endClientExecution(awsRequestMetrics, request, response);
        }
    }
<p>
Starts a Composition from a stage based on the configuration provided in the request.
</p>
<p>
A Composition is an ephemeral resource that exists after this endpoint returns successfully. Composition stops
and the resource is deleted:
</p>
<ul>
<li>
<p>
When <a>StopComposition</a> is called.
</p>
</li>
<li>
<p>
After a 1-minute timeout, when all participants are disconnected from the stage.
</p>
</li>
<li>
<p>
After a 1-minute timeout, if there are no participants in the stage when StartComposition is called.
</p>
</li>
<li>
<p>
When broadcasting to the IVS channel fails and all retries are exhausted.
</p>
</li>
<li>
<p>
When broadcasting is disconnected and all attempts to reconnect are exhausted.
</p>
</li>
</ul>

@param startCompositionRequest
@return Result of the StartComposition operation returned by the service.
@throws ResourceNotFoundException
@throws ValidationException
@throws AccessDeniedException
@throws InternalServerException
@throws ServiceQuotaExceededException
@throws ConflictException
@throws PendingVerificationException
@sample AmazonIVSRealTime.StartComposition
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/ivs-realtime-2020-07-14/StartComposition" target="_top">AWS
     API Documentation</a>
aws-java-sdk-ivsrealtime/src/main/java/com/amazonaws/services/ivsrealtime/AmazonIVSRealTimeClient.java