class Protocol::HTTP::Headers

@returns An enumerator which is suitable for iterating over trailers.
@yields {|name, value| ...} the trailing headers if a block is given.
@parameter names [Array] The trailer header names which will be added later.

A sender that intends to generate one or more trailer fields in a message should generate a trailer header field in the header section of that message to indicate which fields might be present in the trailers.

This method is typically used after headers are sent to capture any additional headers which should then be sent as trailers.

Record the current headers, and prepare to add trailers.

def trailer!(&block)
	@tail ||= @fields.size
	
	return trailer(&block)
end