Implement "resize windows using mouse" in my custom layouts?

[prize-goof]

Is your feature request related to a problem? Please describe.
I want my custom layouts (written in javascript) to support the "resize windows using mouse" feature just like the built-in two-pane layout. If I just write the code to calculate window size, then when I drag to resize windows, the layout won't update to new size.

Describe the solution you'd like
Is there already an API for the event of mouse resizing a window? I have not found it in the docs. Could you tell me how to do this if it is already implemented? If not implemented yet, could this feature be implemented?

[ianyh]

It is not currently possible, but would be possible to implement.

[prize-goof]

Thank you! I am looking forward for an implementation of that!