question: private void consumePreNestedScroll ( int dx , int dy , int [ ] consumed ) { if ( mOverScrollEffect == OverScrollEffect . BOUNCE && mUnconsumedOverScrollOffset != 0 ) { int destOffset = mUnconsumedOverScrollOffset - dy ; if ( ! MathUtils . sameSign ( destOffset , mUnconsumedOverScrollOffset ) ) { destOffset = 0 ; } else if ( Math . abs ( destOffset ) > Math . abs ( mUnconsumedOverScrollOffset ) ) { destOffset = mUnconsumedOverScrollOffset ; } consumed [ 0 ] = 0 ; consumed [ 1 ] = mUnconsumedOverScrollOffset - destOffset ; mUnconsumedOverScrollOffset = destOffset ; setScrollingOffset ( getUnconsumedScrollingOffset ( ) ) ; } }
target:  Consume the pre nested scroll before all behaviors if need.