input:
```rust
/// Battery service
#[gatt_service(uuid = "180f")]
struct BatteryService {
    /// Percentage charge left
    ///
    /// Multiline
    #[characteristic(uuid = "2a19", read, write, notify, value = 99, on_read = battery_level_on_read)]
    #[descriptor(uuid = "2a20", read, on_read = battery_level_on_read)]
    #[descriptor(uuid = "2a20", read, value = "Demo description")]
    level: u8,
    non_characteristic_field: f32,
    /// minutes until empty
    #[characteristic(uuid = "2a22", read, write, notify, value = 42.0)]
    #[descriptor(uuid = "2a21", read, value = VAL)]
    #[descriptor(uuid = "2a25", read, value = [8,8])]
    #[descriptor(uuid = "2b26", read, value = 42u8.to_le_bytes())]
    rate_of_discharge: f32,
    #[characteristic(uuid = "2a23", read, write, notify, value = [52u8, 10u8])]
    tx: [u8; 2],
    #[characteristic(uuid = "2a38", read, notify)]
    /// Testing something
    notify: [u8; 8],
    #[characteristic(uuid = "2a24", read, write, notify, value = Vec::from_slice(&[1,2,3]).unwrap())]
    rx: Vec<u8, 3>,
}
```

expands to:
```rust
struct BatteryService {
    non_characteristic_field: f32,
    /// Percentage charge left
    ///
    /// Multiline
    level: Characteristic<u8>,
    /// minutes until empty
    rate_of_discharge: Characteristic<f32>,
    tx: Characteristic<[u8; 2]>,
    /// Testing something
    notify: Characteristic<[u8; 8]>,
    rx: Characteristic<Vec<u8, 3>>,
    handle: AttributeHandle,
}