public Procedure<TEnvironment> getResult(long procId) {
    CompletedProcedureRetainer<TEnvironment> retainer = completed.get(procId);
    if (retainer == null) {
      return null;
    } else {
      return retainer.getProcedure();
    }
  }
Send an abort notification to the specified procedure. Depending on the procedure
implementation, the abort can be considered or ignored.
@param procId                the procedure to abort
@param mayInterruptIfRunning if the proc completed at least one step, should it be aborted?
@return true if the procedure exists and has received the abort, otherwise false.
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java