public RouteSpec setHop(int i, String hop) {
        hops.set(i, hop);
        return this;
    }
Sets the hop name for a given index.

@param i   The index of the hop to set.
@param hop The hop to set.
@return This, to allow chaining.
messagebus/src/main/java/com/yahoo/messagebus/routing/RouteSpec.java