presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/CheckTaskCompletionOnBufferFinish/CheckTaskCompletionOnBufferFinish
class CheckTaskCompletionOnBufferFinish:        public CheckTaskCompletionOnBufferFinish(SqlTaskExecution sqlTaskExecution)
        {
            // we are only checking for completion of the task, so don't hold up GC if the task is dead
            this.sqlTaskExecutionReference = new WeakReference<>(sqlTaskExecution);
        }