Function S2Loop.initialize
Initialize a loop with given vertices. The last vertex is implicitly connected to the first. All points should be unit length. Loops must have at least 3 vertices (except for the "empty" and "full" loops, see kEmpty and kFull). This method may be called multiple times.
void initialize(RangeT)
(
RangeT vertexRange
)
if (isInputRange!RangeT);