No overload matches this call.
Overload 1 of 3, '(handler: ServeHandler): Server', gave the following error.
Argument of type '(request: Request) => Promise<Response | undefined>' is not assignable to parameter of type 'ServeHandler'.
Type 'Promise<Response | undefined>' is not assignable to type 'Response | Promise<Response>'.
Type 'Promise<Response | undefined>' is not assignable to type 'Promise<Response>'.
Type 'Response | undefined' is not assignable to type 'Response'.
Type 'undefined' is not assignable to type 'Response'. Overload 2 of 3, '(options: ServeInit & (ServeOptions | ServeTlsOptions)): Server', gave the following error.
No overload matches this call.
Overload 1 of 3, '(handler: ServeHandler): Server', gave the following error.
Argument of type '(request: Request) => Promise<Response | undefined>' is not assignable to parameter of type 'ServeHandler'.
Type 'Promise<Response | undefined>' is not assignable to type 'Response | Promise<Response>'.
Type 'Promise<Response | undefined>' is not assignable to type 'Promise<Response>'.
Type 'Response | undefined' is not assignable to type 'Response'.
Type 'undefined' is not assignable to type 'Response'. Overload 2 of 3, '(options: ServeInit & (ServeOptions | ServeTlsOptions)): Server', gave the following error.
