presto-main/src/main/java/io/prestosql/server/TaskResource.java/TaskResource/acknowledgeResults
class TaskResource:    @GET
    @Path("{taskId}/results/{bufferId}/{token}/acknowledge")
    public void acknowledgeResults(
            @PathParam("taskId") TaskId taskId,
            @PathParam("bufferId") OutputBufferId bufferId,
            @PathParam("token") final long token)
    {
        requireNonNull(taskId, "taskId is null");
        requireNonNull(bufferId, "bufferId is null");

        taskManager.acknowledgeTaskResults(taskId, bufferId, token);
    }