perf: use buffered chans for requests (#1146)

frankenphp.go

@@ -333,7 +333,7 @@ func Init(options ...Option) error {
 
 	shutdownWG.Add(1)
 	done = make(chan struct{})
-	requestChan = make(chan *http.Request)
+	requestChan = make(chan *http.Request, opt.numThreads)
 	initPHPThreads(opt.numThreads)
 
 	if C.frankenphp_init(C.int(opt.numThreads)) != 0 {