Refactor:Mv mod visitor vfs under crates_io

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

src/drivers.rs

@@ -2,11 +2,6 @@ use std::path::{Path, PathBuf};
 
 use crate::BinstallError;
 
-mod vfs;
-
-mod visitor;
-use visitor::ManifestVisitor;
-
 mod version;
 use version::find_version;
 

src/drivers/crates_io.rs

@@ -6,9 +6,14 @@ use crates_io_api::AsyncClient;
 use log::debug;
 use url::Url;
 
-use super::{find_version, ManifestVisitor};
+use super::find_version;
 use crate::{helpers::*, BinstallError, Meta, TarBasedFmt};
 
+mod vfs;
+
+mod visitor;
+use visitor::ManifestVisitor;
+
 /// Fetch a crate Cargo.toml by name and version from crates.io
 pub async fn fetch_crate_cratesio(
     name: &str,