add prefetch config value

deltachat-ffi/deltachat.h

@@ -350,6 +350,7 @@ char*           dc_get_blobdir               (const dc_context_t* context);
  *                    The type `jitsi:` may be handled by external apps.
  *                    If no type is prefixed, the videochat is handled completely in a browser.
  * - `bot`          = Set to "1" if this is a bot. E.g. prevents adding the "Device messages" and "Saved messages" chats.
+ * - `prefetch`     = 1=fetch most recent existing messages on configure (default), 0=do not fetch on configure
  *
  * If you want to retrieve a value, use dc_get_config().
  *

src/config.rs

@@ -69,6 +69,9 @@ pub enum Config {
     #[strum(props(default = "0"))] // also change MediaQuality.default() on changes
     MediaQuality,
 
+    #[strum(props(default = "1"))]
+    Prefetch,
+
     #[strum(props(default = "0"))]
     KeyGenType,
 

src/configure/mod.rs

@@ -353,11 +353,13 @@ async fn configure(ctx: &Context, param: &mut LoginParam) -> Result<()> {
     e2ee::ensure_secret_key_exists(ctx).await?;
     info!(ctx, "key generation completed");
 
-    job::add(
-        ctx,
-        job::Job::new(Action::FetchExistingMsgs, 0, Params::new(), 0),
-    )
-    .await;
+    if ctx.get_config_bool(Config::Prefetch).await {
+        job::add(
+            ctx,
+            job::Job::new(Action::FetchExistingMsgs, 0, Params::new(), 0),
+        )
+        .await;
+    }
 
     progress!(ctx, 940);
     update_device_chats_handle.await?;