func (g *Group) ServeFilesCustom(path string, fs *fasthttp.FS) {
	g.router.ServeFilesCustom(g.prefix+path, fs)
}
ServeFilesCustom serves files from the given file system settings.
The path must end with "/{filepath:*}", files are then served from the local
path /defined/root/dir/{filepath:*}.
For example if root is "/etc" and {filepath:*} is "passwd", the local file
"/etc/passwd" would be served.
Internally a fasthttp.FSHandler is used, therefore http.NotFound is used instead
of the Router's NotFound handler.
Use:
router.ServeFilesCustom("/src/{filepath:*}", *customFS)
package router
import "github.com/valyala/fasthttp"
func (g *Group) Group(path string) *Group {
	return g.router.Group(g.prefix + path)
}
func (g *Group) GET(path string, handler fasthttp.RequestHandler) {
	g.router.GET(g.prefix+path, handler)
}
func (g *Group) HEAD(path string, handler fasthttp.RequestHandler) {
	g.router.HEAD(g.prefix+path, handler)
}
func (g *Group) POST(path string, handler fasthttp.RequestHandler) {
	g.router.POST(g.prefix+path, handler)
}
func (g *Group) PUT(path string, handler fasthttp.RequestHandler) {
	g.router.PUT(g.prefix+path, handler)
}
func (g *Group) PATCH(path string, handler fasthttp.RequestHandler) {
	g.router.PATCH(g.prefix+path, handler)
}
func (g *Group) DELETE(path string, handler fasthttp.RequestHandler) {
	g.router.DELETE(g.prefix+path, handler)
}
func (g *Group) CONNECT(path string, handler fasthttp.RequestHandler) {
	g.router.CONNECT(g.prefix+path, handler)
}
func (g *Group) OPTIONS(path string, handler fasthttp.RequestHandler) {
	g.router.OPTIONS(g.prefix+path, handler)
}
func (g *Group) TRACE(path string, handler fasthttp.RequestHandler) {
	g.router.TRACE(g.prefix+path, handler)
}
func (g *Group) ANY(path string, handler fasthttp.RequestHandler) {
	g.router.ANY(g.prefix+path, handler)
}
func (g *Group) ServeFiles(path string, rootPath string) {
	g.router.ServeFiles(g.prefix+path, rootPath)
}