[parse] adding short disconnect msg support

[dscso]

#291

[dscso]

Idk the second commit of the PR is much less important, but in a very data limited environment this could make sense if you are reopening the MQTT connection very often

[TheNeikos]

Ah good catch!

There is similar logic for this like this in the repo:

cloudmqtt/mqtt-format/src/v5/packets/puback.rs

Lines 58 to 68 in fdcfb58

	let reason = if input.is_empty() {
	PubackReasonCode::Success
	} else {
	PubackReasonCode::parse(input)?
	};
	let properties = if input.is_empty() {
	PubackProperties::new()
	} else {
	PubackProperties::parse(input)?
	};

Do you think you could adapt it to this?

[dscso]

true, looks better :). Done

[TheNeikos]

Thank you!