Fix #1085 (#1091)

httplib.h

@@ -1487,10 +1487,10 @@ inline T Response::get_header_value(const char *key, size_t id) const {
 template <typename... Args>
 inline ssize_t Stream::write_format(const char *fmt, const Args &...args) {
   const auto bufsiz = 2048;
-  std::array<char, bufsiz> buf;
+  std::array<char, bufsiz> buf{};
 
 #if defined(_MSC_VER) && _MSC_VER < 1900
-  auto sn = _snprintf_s(buf.data(), bufsiz - 1, buf.size() - 1, fmt, args...);
+  auto sn = _snprintf_s(buf.data(), bufsiz, _TRUNCATE, fmt, args...);
 #else
   auto sn = snprintf(buf.data(), buf.size() - 1, fmt, args...);
 #endif
@@ -5673,7 +5673,7 @@ inline void ClientImpl::close_socket(Socket &socket) {
 
 inline bool ClientImpl::read_response_line(Stream &strm, const Request &req,
                                            Response &res) {
-  std::array<char, 2048> buf;
+  std::array<char, 2048> buf{};
 
   detail::stream_line_reader line_reader(strm, buf.data(), buf.size());