offline mode, connectivity check, backup cdn

probably the last real update for this codebase

src/structs.rs

@@ -48,6 +48,12 @@ pub struct Config {
     pub skip_redist: bool,
     #[serde(default)]
     pub prerelease: bool,
+    #[serde(default)]
+    pub cdn_url: String,
+    #[serde(default)]
+    pub offline: bool,
+    #[serde(default)]
+    pub skip_connectivity_check: bool,
 }
 
 impl Default for Config {
@@ -63,6 +69,9 @@ impl Default for Config {
             use_https: true,
             skip_redist: false,
             prerelease: false,
+            cdn_url: String::default(),
+            offline: false,
+            skip_connectivity_check: false,
         }
     }
 }