ngx_http_upstream_status_variable

len = r->upstream_states->nelts * (3 + 2);

write status to string, one status str len would be 3 in most case, like 200, 302, 404....
but if upstream multi times, may be add ' : ' as separator

so, string len may be nelts*3 + (nelts-1)*3 = 6nelts - 3 != nelts * (3 + 2);

what's wrong here?