Checks if the input data can be handled by this class. Throws an error if it can't handle the data.
Input data that would be handled potentially.
A promise resolving if this input can be handled, rejecting with an Error if not.
The data to handle.
The result of the handle function of the handler.
A MetadataWriter that takes a map directly converting metadata predicates to headers. The header value(s) will be the same as the corresponding object value(s).