Don't expose BoxFuture in public API

`ObjectStore::get` calls itself recursively, so the returned future
needs to be boxed. However, this is an implementation detail, there's no
reason to expose it in the public API. Instead, we can move the
recursive call to a separate `get_impl` function that handles the
boxing, and `get` can just be a standard async function.

async-nats/src/jetstream/object_store/mod.rs

@@ -109,14 +109,19 @@ impl ObjectStore {
     /// # Ok(())
     /// # }
     /// ```
-    pub fn get<'bucket, 'future, T>(
+    pub async fn get<T: AsRef<str> + Send>(&self, object_name: T) -> Result<Object, GetError> {
+        self.get_impl(object_name).await
+    }
+
+    fn get_impl<'bucket, 'future, T>(
         &'bucket self,
         object_name: T,
     ) -> BoxFuture<'future, Result<Object, GetError>>
     where
         T: AsRef<str> + Send + 'future,
         'bucket: 'future,
     {
+        // Future needs to be boxed because get_impl calls itself recursively
         Box::pin(async move {
             let object_info = self.info(object_name).await?;
             if let Some(ref options) = object_info.options {
@@ -125,7 +130,7 @@ impl ObjectStore {
                         let link_name = link_name.clone();
                         debug!("getting object via link");
                         if link.bucket == self.name {
-                            return self.get(link_name).await;
+                            return self.get_impl(link_name).await;
                         } else {
                             let bucket = self
                                 .stream
@@ -135,7 +140,7 @@ impl ObjectStore {
                                 .map_err(|err| {
                                 GetError::with_source(GetErrorKind::Other, err)
                             })?;
-                            let object = bucket.get(&link_name).await?;
+                            let object = bucket.get_impl(&link_name).await?;
                             return Ok(object);
                         }
                     } else {