And whereas the United States are engaged in a just and necessary war . . . against the King of England . . . and as the most practicable way for the troops of the United States to some of the posts and forts is by passing through the country of the Delaware nation, the [Delaware Indians], on behalf of themselves and their nation, do hereby [guarantee] and agree to give a free passage through their country to the troops aforesaid, . . . affording to said troops such supplies of corn, meat, horses . . .
-Treaty with the Delawares, 1778 Courtesy of The Avalon Project at Yale Law School
According to the excerpt, in what way did the Delaware Indians contribute to the military efforts of the Colonists during the American Revolution?