UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.81 Safari/537.36

Steps to reproduce the problem:
1. Switch to the source tab
2. Open big file

What is the expected behavior?
It should not take 30 seconds. It should load a part of the file to make the visible part almost immediately visible.

What went wrong?
It takes loooooooooooooong.

Did this work before? Yes Never had this problem with big files before. Maybe I haven't tried enough of them though.

Chrome version: 69.0.3497.81  Channel: n/a
OS Version: OS X 10.13.4
Flash Version: 

I can't share the file, it is private. What other info could help you?