class Async::HTTP::Client

def call(request)
	request.scheme ||= self.scheme
	request.authority ||= self.authority
	
	attempt = 0
	
	# We may retry the request if it is possible to do so. https://tools.ietf.org/html/draft-nottingham-httpbis-retry-01 is a good guide for how retrying requests should work.
	begin
		attempt += 1
		
		# As we cache pool, it's possible these pool go bad (e.g. closed by remote host). In this case, we need to try again. It's up to the caller to impose a timeout on this. If this is the last attempt, we force a new connection.
		connection = @pool.acquire
		
		response = make_response(request, connection)
		
		# This signals that the ensure block below should not try to release the connection, because it's bound into the response which will be returned:
		connection = nil
		
		return response
	rescue Protocol::RequestFailed
		# This is a specific case where the entire request wasn't sent before a failure occurred. So, we can even resend non-idempotent requests.
		if connection
			@pool.release(connection)
			connection = nil
		end
		
		if attempt < @retries
			retry
		else
			raise
		end
	rescue SocketError, IOError, EOFError, Errno::ECONNRESET, Errno::EPIPE
		if connection
			@pool.release(connection)
			connection = nil
		end
		
		if request.idempotent? and attempt < @retries
			retry
		else
			raise
		end
	ensure
		@pool.release(connection) if connection
	end
end