uni.onBLEConnectionStateChange CALLBACK.value是会自动分包吗？每个包为20个大小？为什么会出现不触发或者丢包的现象

uni.onBLEConnectionStateChange CALLBACK.value是会自动分包吗？每个包为20个大小？为什么会出现不触发或者丢包的现象

uni.onBLECharacteristicValueChange(res => {  
    let resHex = ab2hex(res.value)  
    let result = hexCharCodeToStr(resHex)  
    console.log('消息:', resHex)  
    emit('newMsg', String(result))  
})  

const hexArr = Array.prototype.map.call(  
    new Uint8Array(buffer),  
    function (bit) {  
      return '00'+bit.toString(16)).slice(-2)  
    }  
  )  
  return hexArr.join('')  
}