http: optimize HTTP request thread we don't need a mutex at all, in fact all we need is an atomic boolean to signify whether the thread is cancelled. curl options are now for the most part handled by a separate function to keep them in sync between non-threaded and threaded implementations

#include "fmt/format.h"

int main(int argc, char** argv) {
  for (int i = 0; i < argc; ++i) fmt::print("{}: {}\n", i, argv[i]);
}