class Server

def each(task: Task.current)
	task.annotate("Reading #{self.version} requests for #{self.class}.")
	
	while request = next_request
		if body = request.body
			finishable = Finishable.new(body)
			request.body = finishable
		end
		
		response = yield(request, self)
		version = request.version
		body = response&.body
		
		if hijacked?
			body&.close
			return
		end
		
		task.defer_stop do
			# If a response was generated, send it:
			if response
				trailer = response.headers.trailer!
				
				# Some operations in this method are long running, that is, it's expected that `body.call(stream)` could literally run indefinitely. In order to facilitate garbage collection, we want to nullify as many local variables before calling the streaming body. This ensures that the garbage collection can clean up as much state as possible during the long running operation, so we don't retain objects that are no longer needed.
				
				if body and protocol = response.protocol
					# We force a 101 response if the protocol is upgraded - HTTP/2 CONNECT will return 200 for success, but this won't be understood by HTTP/1 clients:
					write_response(@version, 101, response.headers)
					
					# At this point, the request body is hijacked, so we don't want to call #finish below.
					request = nil
					response = nil
					
					if body.stream?
						return body.call(write_upgrade_body(protocol))
					else
						write_upgrade_body(protocol, body)
					end
				elsif response.status == 101
					# This code path is to support legacy behavior where the response status is set to 101, but the protocol is not upgraded. This may not be a valid use case, but it is supported for compatibility. We expect the response headers to contain the `upgrade` header.
					write_response(@version, response.status, response.headers)
					
					# Same as above:
					request = nil
					response = nil
					
					if body.stream?
						return body.call(write_tunnel_body(version))
					else
						write_tunnel_body(version, body)
					end
				else
					write_response(@version, response.status, response.headers)
					
					if request.connect? and response.success?
						# Same as above:
						request = nil
						response = nil
						
						if body.stream?
							return body.call(write_tunnel_body(version))
						else
							write_tunnel_body(version, body)
						end
					else
						head = request.head?
						
						# Same as above:
						request = nil
						response = nil
						
						write_body(version, body, head, trailer)
					end
				end
				
				# We are done with the body:
				body = nil
			else
				# If the request failed to generate a response, it was an internal server error:
				write_response(@version, 500, {})
				write_body(version, nil)
				
				request&.finish
			end
			
			if finishable
				finishable.wait(@persistent)
			else
				# Do not remove this line or you will unleash the gods of concurrency hell.
				task.yield
			end
		rescue => error
			raise
		ensure
			body&.close(error)
		end
	end
end