docs: private static InputStream inputStreamFromFile(String relativePathPrefix, String src) throws IOException {
          File file = getFile(relativePathPrefix, src);
          if (!file.exists()) {
              if (src.length() > 0 && src.charAt(0) == File.separatorChar) {
                  file = getFile(relativePathPrefix, src.substring(1));
              }
              if (!file.exists()) {
                  file = null;
              }
          } else if (!file.isFile() || !file.canRead()) {
              file = null;
          }
          if (file != null) {
              return new FileInputStream(file);
          }
          return null;
      }