public static boolean canFinish(QueryFragmentInfo fragment) {
    return fragment.canFinish();
  }
Check whether a task can run to completion or may end up blocking on it's sources.
This currently happens via looking up source state.
TODO: Eventually, this should lookup the Hive Processor to figure out whether
it's reached a state where it can finish - especially in cases of failures
after data has been fetched.

@return true if the task can finish, false otherwise
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/QueryFragmentInfo.java