Bootstrap：固定流体布局中的沟槽宽度？

I want to have different layouts like [left|content|right] and [left|content] or [content|right] when using the fluid layout the gutter between the "cells" is also fluid and has a percentage value. But I would like to have a fixed width for the gutter like 10px or 20px between the left/right and content areas.I want to have different layouts like [left|con