The docs lack a description of all available methods and their expected params and types

I'm trying to figure out if I can pass an ArrayBuffer to the file writer, but the docs don't have any kind of API documentation, only some scattered examples. I shouldn't have to go and read through the source to find out what each function really accepts. It would be a lot better if the docs included some standard, concise API documentation containing the following:
- Method name
- Parameters, whether they're optional, and their accepted types
- Return value

Start by inventorying the file plugin methods covered by the existing scattered examples and comparing that list with the implementation. Document each method's name, parameter optionality and accepted types, and return value; done means the API documentation covers all available methods without requiring readers to inspect the source.

Written by the indexing model from the issue text.