docs: @Nonnull
      public static String[] mapToEnv(@Nonnull Map<String,String> m) {
          String[] r = new String[m.size()];
          int idx=0;
  
          for (final Map.Entry<String,String> e : m.entrySet()) {
              r[idx++] = e.getKey() + '=' + e.getValue();
          }
          return r;
      }