Add length to get the entire duration of midi, similar to get_end_time

[jonata]

Hi!

I see some discussion on #80. I see that get_end_time does not give me the duration of the midi file in some cases. For a reference, if you look at mido length property, it would calculate all messages' times to get the desired duration value. What about adding this length property just like mido does?

Thanks!

[craffel]

The get_end_time does exactly that - it provides the time of the final event (across all event types). The issue you linked was proposing that get_end_time only operate on note events.

[jonata]

Sorry, but in my tests I am getting different results using get_end_time and mido's length. So get_end_time does not do "exactly that". It seems that it does not get "all event types".