I2cdev doesn't implement Debug

[long568]

I try ro define a struct like this:

use linux_embedded_hal::I2cdev;
use pwm_pca9685::{Address, Channel, Pca9685};

#[derive(Debug)]
pub struct Executor {
    ll: Leg,
    rl: Leg,
    lf: Foot,
    rf: Foot,
    pwm: Pca9685<I2cdev>, // ERROR
}

but, I got a error:
I2cdev doesn't implement Debug
the trait Debug is not implemented for I2cdev, which is required by &Pca9685<I2cdev>: Debug
the trait Debug is implemented for Pca9685<I2C>
Dose I2cdev define with [drive(Debug)] ?