lib: Return size in write functions

[nmsv]

Returning size of written payload is usually a sane thing to do. Shouldn't hurt anyone.

[patrickelectric]

It appears that something is wrong with GitHub, I can't get the "approve and run" button to work since it redirects to page 500 error. Will try again later.

[mrpollo]

Can't get it to work for me either not sure what's going on.

[hamishwillee]

Same, does not work. You might have to contact github.

[mrpollo]

I opened a support ticket with GitHub, I'll post back

[mrpollo]

@patrickelectric not sure if #97 helped unblock things or if my support ticket, but CI is running, but failing, on an error that I can't really understand, I'll leave it to someone smarter than me to figure it out

[mrpollo]

@nmsv looks like CI is reporting a real error

     Running `/home/runner/work/rust-mavlink/rust-mavlink/target/debug/deps/process_log_files-6ac8326e72b327a0 --nocapture`
running 1 test
Processing file: /tmp/testlogs/ArduCopter-test.tlog
thread 'process_files::all' panicked at 'Unable to hit the necessary amount of matches', tests/process_log_files.rs:71:9
recv error: Custom { kind: UnexpectedEof, error: "failed to fill whole buffer" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Number of parsed messages: 0
test process_files::all ... FAILED

failures:

failures:
    process_files::all


test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.57s

error: test failed, to rerun pass '--test process_log_files'

[nmsv]

@mrpollo
@patrickelectric
@hamishwillee

I'm able to reproduce the failed test on master (91f3966):
cargo test --verbose --features all-dialects -- --nocapture
So, as far as I understand, this is not related to the PR.

[patrickelectric]

Merged in #100