@Override
  public synchronized String toString() {
    return getClass().getSimpleName() + " for " + object + ", ready=" + isReady() + ", "
      + suspendedProcedures;
  }
Access to suspendedProcedures is 'synchronized' on this object, but it's fine to return it here
for tests.
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureEvent.java