@Override
  protected void deserializeStateData(ProcedureStateSerializer serializer) throws IOException {
    final AssignRegionStateData state = serializer.deserialize(AssignRegionStateData.class);
    setTransitionState(state.getTransitionState());
    setRegionInfo(ProtobufUtil.toRegionInfo(state.getRegionInfo()));
    forceNewPlan = state.getForceNewPlan();
    if (state.hasTargetServer()) {
      this.targetServer = ProtobufUtil.toServerName(state.getTargetServer());
    }
    if (state.hasAttempt()) {
      setAttempt(state.getAttempt());
    }
  }
Leave here only for checking if we can successfully start the master.
@deprecated Do not use any more.
@see TransitRegionStateProcedure
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignProcedure.java