Set fillViewport=true ?

[SatyaFariz]

Hello, thanks for this super awesome library !
I made my own wrapper for native android TabLayout that works well with this lib and ViewPagerAndroid in order to achieve collapsible tab header effect. However when I scroll up this leaves an empty white space at the very bottom of the screen. After days of investigation I can confirm that the nested scroll view doesn't take the available vertical space. Taking reference from this stackoverflow post, seems like I need to set fillViewport=true to the scroll view. How can I do that ? if it's not currently possible please consider this a feature request.