mJs UART API performance problems about mjs HOT 4 CLOSED

var SerialPort = require("serialport").SerialPort
var serialPort = new SerialPort("/dev/tty.usbserial-A94JN1PL", {
  baudrate: 115200, autoOpen: false,
});

serialPort.open(function (error) {
  if ( error ) {
    console.log('failed to open: '+error);
  } else {
    console.log('open');
    serialPort.on('data', function(data) {
      console.log('data received: ' + data);
      if(data.indexOf('talkstart')> -1) {
        let vd = "1234567890123456789012345678901234567890123456";
        console.log("data packet len: " + vd.length);
        let pktNum = 0;
        let id = setInterval(function(){
          serialPort.write(vd, function(err, results) {
            if(err) {
              console.log('err ' + err);
            } else {
              pktNum++;
              if(pktNum>499) clearInterval(id);
            }
          });
        }, 20); // 46bytes/20ms, 23000 bytes total
      }
    });

  }
});

// Load Mongoose OS API
load('api_timer.js');
load('api_uart.js');
load('api_sys.js');

let rxAcc = ""; // to store all the bytes received
let rx_total = 0; // total number of received bytes
// Configure UART at 115200 baud
UART.setConfig(1,{
  baudRate: 115200,
});

UART.setDispatcher(1, function(uartNo, ud) {
  let ra = UART.readAvail(uartNo);
  if (ra > 0) {
    let data = UART.read(uartNo);
    rxAcc += data;
    rx_total += data.length;  
    print("len:", data.length, "total:", rx_total);
  }
}, null);

// Enable Rx
UART.setRxEnabled(1, true);

// Start communication after 2 seconds
Timer.set(2000 /* milliseconds */, false /* repeat */, function() {
  // signal, a nodejs serialport connected to EPS32 will start sending data
  UART.write(1,"go");
}, null);

Timer.set(17000 /* milliseconds */, false /* repeat */, function() {
  print("==================");
  print("rxAcc lent:", rxAcc.length, "rx_total:", rx_total);
}, null);

'use strict';

var SerialPort = require("serialport")
var serialPort = new SerialPort("/dev/ttyUSB1", {
  baudRate: 115200, autoOpen: false,
});

serialPort.open(function (error) {
  if ( error ) {
    console.log('failed to open: '+error);
  } else {
    console.log('open');
    serialPort.on('data', function(data) {
      console.log('data received: ' + data);
      if(data.indexOf('go')> -1) {
        let vd = "1234567890123456789012345678901234567890123456";
        console.log("data packet len: " + vd.length);
        let pktNum = 0;
        let id = setInterval(function(){
          serialPort.write(vd, function(err, results) {
            if(err) {
              console.log('err ' + err);
            } else {
              pktNum++;
              if(pktNum>499) clearInterval(id);
            }
          });
        }, 20); // 46bytes/20ms, 23000 bytes total
      }
    });

  }
});