@Override
  protected void serializeStateData(ProcedureStateSerializer serializer) throws IOException {
    SwitchRpcThrottleRemoteStateData.Builder builder =
      SwitchRpcThrottleRemoteStateData.newBuilder();
    builder.setTargetServer(ProtobufUtil.toServerName(targetServer))
      .setRpcThrottleEnabled(rpcThrottleEnabled).setState(state).build();
    if (this.remoteError != null) {
      ErrorHandlingProtos.ForeignExceptionMessage fem =
        ForeignExceptionUtil.toProtoForeignException(remoteError);
      builder.setError(fem);
    }
    serializer.serialize(builder.build());
  }
The procedure to switch rpc throttle on region server
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/SwitchRpcThrottleRemoteProcedure.java