writing `&[]` to a sampling port yields an error

[wucke13]

I think its valid to write an empty message to a sampling port, to clear all data that was in it before.

[florianhartung]

ARINC653 P1 3.6.2.1.2 actually defines that writing an empty buffer should result in InvalidParam being returned. This is already implemented correctly.

However when trying to write an empty buffer, a653rs::apex::types::Error::WriteError is falsely returned. It turns out that the check whether a buffer is empty is done in the a653rs crate itself, when validating the buffer size (see here).

[wucke13]

closed via https://github.com/DLR-FT/a653rs/issues/37