Add Connection#finished_request?

[c960657]

When using persistent connections there is no easy way to check if the entire body of the previous request has been consumed before sending a new request, e.g. if an exception was raised while reading the body.

Add Connection#finished? which does the same check as the guards in Connection#send_request.

http/lib/http/connection.rb

Lines 69 to 76 in 32a2ae6

	def send_request(req)
	if @pending_response
	raise StateError, "Tried to send a request while one is pending already. Make sure you read off the body."
	end
	if @pending_request
	raise StateError, "Tried to send a request while a response is pending. Make sure you read off the body."
	end

[tarcieri]

Thanks!