code: private Map<String, FileDescriptor> getCache(Iterable<FileDescriptor> fileDescriptors) {
          Map<String, FileDescriptor> cache = new HashMap<>();
          for (FileDescriptor fileDescriptor : fileDescriptors) {
              cache.put(fileDescriptor.getFileName(), fileDescriptor);
          }
          return cache;
      }
docs: Creates cache map from the given collection of file descriptors.
  
  @param fileDescriptors The collection of file descriptors.
  @return The cache map.