If you consider the components of digestion - mechanical / physical digestion, chemical digestion, absorption - a liquid carb source will get digested faster because there is less need for physical breakdown of the food in the stomach.
Carbs get absorbed by the villi in the small intestine. So the faster it gets to the small intestine, the faster it will get absorbed. So liquids are faster than solids.
And for that reason - if everything else is the same - you might want to do a little bit of a longer pre-bolus for a liquid than a solid, because the sugar will hit your bloodstream a little faster.
But for the amount of insulin, your body does not care how the glucose got there. Once it is broken down into glucose, it is all the same - C6H12O6.
So it will get there faster, but will be the same as far as what the glucose is.
I know some people do different things for fat content or whatever. But if you were to compare it to the same exact thing but solid, the only difference would be that a liquid would hit your bloodstream a little faster than a solid.
Also, if your stomach is empty, it will also be faster than if you had a full stomach.