Type Alias MakePfMethod 

pub type MakePfMethod = dyn Fn(PluginConfig) -> Result<Box<dyn Fn(Request<SgBody>, Inner) -> BoxFuture<'static, Response<SgBody>> + Send + Sync + 'static>, BoxError> + Send + Sync + 'static;

Plugin function maker, which received a PluginConfig and return a [InnerBoxPf]