docs: public static boolean isAbsoluteUnixOrWindowsPath(final String path) {
          if (path != null) {
              int length = path.length();
              if (length > 0) {
                  char c0 = path.charAt(0);
                  if (c0 == '/') {
                      return true;   // Absolute Unix path
                  } else if (length > 1) {
                      char c1 = path.charAt(1);
                      if (c0 == '\\' && c1 == '\\') {
                          return true;   // Absolute UNC pathname "\\\\foo"
                      } else if (length > 2 && c1 == ':' && path.charAt(2) == '\\' && isDriveLetter(c0) ) {
                          return true; // Absolute local pathname "z:\\foo"
                      }
                  }
  
              }
          }
          return false;
      }