HomeBridge critically slowed down by Meross plugin
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**Describe The Bug:**
Each time you access any Meross device through the plugin, it returns

```
[2/3/2021 7:33:10] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' was slow to respond! See https://git.io/JtMGR for more info.
[2/3/2021 7:33:16] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' didn't respond at all!. Please check that you properly call the callback! See https://git.io/JtMGR for more info.
```


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**To Reproduce:**
You only have to use it, and the HomeBridge Console will display the message shown above.  Answers to HB are incredibly slow, up to a point it takes seconds to update the Meross state

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**Expected behavior:**
Normal, previous to last version, behaviour could be great.

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**Logs:**


```
[2/3/2021 7:33:10] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' was slow to respond! See https://git.io/JtMGR for more info.
[2/3/2021 7:33:16] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' didn't respond at all!. Please check that you properly call the callback! See https://git.io/JtMGR for more info.
```

<!-- Bug reports that do not contain logs may be closed without warning. -->

```
[2/3/2021 7:33:10] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' was slow to respond! See https://git.io/JtMGR for more info.
[2/3/2021 7:33:16] [homebridge-meross] This plugin slows down Homebridge. The read handler for the characteristic 'On' didn't respond at all!. Please check that you properly call the callback! See https://git.io/JtMGR for more info.
```

**Homebridge Config:**

```json
```

**Screenshots:**

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# **Environment:**

- **Node.js Version**: v14.15.3
- **NPM Version**: v6.14.9
- **Homebridge Version**: v1.3.1
- **Homebridge Meross Plugin Version**: homebridge-meross v3.5.0
- **Homebridge Config UI X Plugin Version**: homebridge-meross v3.5.0
- **Operating System**: Homebridge Raspbian v1.0.7 - Raspberry Pi Zero W Rev 1.1 

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