This module is very useful for customizing pipeline execution without having to write an entire module. Returning modules from the config value is also useful for customizing existing modules based on the current set of documents.

If the value is null this module will output the original input document(s). If the value is a IDocument, IEnumerable<T>, or IAsyncEnumerable<T>, the document(s) will be the output(s) of this module. If the value is a IEnumerable<T> or IModule, the module(s) will be executed with the input document(s) as their input and the results will be the output(s) of this module. If the value is an IContentProvider, IContentProviderFactory, or Stream it will be used to get new content for the provided document (or create a new document if the provided document is null). If config value is anything else, the content of the input document will be changed to (or a new document created with) the string value.

If the provided config value does not require a document (for example, it's created with the FromSetting(string, object) factory method) then it will be invoked once for all input documents. If the provided config value does require a document (for example, it's created with the FromDocument(string, object) factory method) then if will be invoked once for each input document.