Dragging the EuiColorStops is a little sluggish. Part of the problem is that EuiColorStopThumb is getting new functions on each EuiColorStops render, forcing each EuiColorStopThumb to re-render even if there are not changes to it.

Throttling the drag event might help limit the renders as well as not passing new function instance into EuiColorStopThumb

cc @thompsongl