feat: optimize mime type

http_handle.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"io/fs"
 	"log/slog"
-	"mime"
 	"net"
 	"os"
 	"path"
@@ -74,7 +73,7 @@ func sendFile(file *os.File, conn net.Conn) {
 
 	parts := strings.Split(fileStat.Name(), ".")
 	ext := "." + parts[len(parts)-1]
-	mime_type := mime.TypeByExtension(ext)
+	mime_type := rh.ExtensionToMimetype[ext]
 	length := fileStat.Size()
 
 	if mime_type == "" {