presto-main/src/main/java/io/prestosql/operator/TaskContext.java/TaskContext/addPipelineContext
class TaskContext:    public PipelineContext addPipelineContext(int pipelineId, boolean inputPipeline, boolean outputPipeline, boolean partitioned)
    {
        PipelineContext pipelineContext = new PipelineContext(
                pipelineId,
                this,
                notificationExecutor,
                yieldExecutor,
                taskMemoryContext.newMemoryTrackingContext(),
                inputPipeline,
                outputPipeline,
                partitioned);
        pipelineContexts.add(pipelineContext);
        return pipelineContext;
    }