Stretching the Timeline

I assume this functionality doesn't exist. But I'd love to be able to stretch all clips on the timeline to change its duration easily, while maintaining relative positions and timing between clips.
Much like this Animation window can do:



I'm using 2018.1, so maybe this functionality exists in later Unity versions?

 

Just select all the keyframes in the timeline with the rectangle selection method, then you will see exactly those vertical bars, you have marked in the above picture, where u can easily adjust the total animation time. All inner keyframes seem to be adjusted proportionally in relation to the total time ...
I use Unity version 2019.3.15, so it might be just a new feature, you didn't have at that time, but actually it took me some time to find this essential feature, too ;-) ...