Function encode_request 

pub fn encode_request(
    method: RpcMethod,
    id: u32,
    target: &[u8],
    request: &RequestParts<'_>,
) -> Result<Vec<Vec<u8>>, RequestEncodeError>

Encode a request as the aux payloads (the bytes that go inside each aux frame AFTER the 6-byte aux header) that carry it, in send order.

target is the device id the request is addressed to; an empty slice is a broadcast every linked drone answers.