@CanIgnoreReturnValue
    public Builder addAttributeProvider(AttributeProvider provider) {
      checkNotNull(provider);
      if (attributeProviders == null) {
        attributeProviders = new HashSet<>();
      }
      attributeProviders.add(provider);
      return this;
    }
Adds an attribute provider for a custom view for the file system to support.
jimfs/src/main/java/com/google/common/jimfs/Configuration.java