code: @Override
      public StartPipelineExecutionResult startPipelineExecution(StartPipelineExecutionRequest request) {
          request = beforeClientExecution(request);
          return executeStartPipelineExecution(request);
      }
docs: <p>
  Starts the specified pipeline. Specifically, it begins processing the latest commit to the source location
  specified as part of the pipeline.
  </p>
  
  @param startPipelineExecutionRequest
  Represents the input of a StartPipelineExecution action.
  @return Result of the StartPipelineExecution operation returned by the service.
  @throws ValidationException
  The validation was specified in an invalid format.
  @throws PipelineNotFoundException
  The specified pipeline was specified in an invalid format or cannot be found.
  @sample AWSCodePipeline.StartPipelineExecution
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/codepipeline-2015-07-09/StartPipelineExecution"
  target="_top">AWS API Documentation</a>