Feature/defmt

[syrtcevvi]

Hello and thank you for your awesome crate and the article!

The problem

In my project I use the defmt logger. I faced the problem with printing the SensorError value to the logs:

use esp_println as _;
use defmt::{error, info, Debug2Format};

match dht11.read() {
    Ok(sensor_reading) => info!(
        "DHT 11 Sensor - Temperature: {} °C, humidity: {} %",
        sensor_reading.temperature, sensor_reading.humidity
    ),
    Err(error) => error!("An error occured: {}", error),
}

Workarounds

The SensorError implements the Debug trait, so it's possible to print it to logs, but it brings a bit overhead and it's unnecessary verbose (Debug2Format):

match dht11.read() {
    Ok(sensor_reading) => info!(
        "DHT 11 Sensor - Temperature: {} °C, humidity: {} %",
        sensor_reading.temperature, sensor_reading.humidity
    ),
    Err(error) => Err(error) => error!("An error occured: {}", defmt::Debug2Format(&error)),
}

Changes

• I've added the optional defmt feature and derived the defmt::Format for the SensorError
• cargo fmt slightly changed the code in a few places