Ankh.HTTP.Response.put_trailer

You're seeing just the function put_trailer, go back to Ankh.HTTP.Response module for more information.
Link to this function

put_trailer(request, name, value)

Specs

put_trailer(t(), Ankh.HTTP.header_name(), Ankh.HTTP.header_value()) :: t()

See Ankh.HTTP.put_trailer/3.