Make sentiment predictions blocking

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

src/threads/data/backfill.rs

@@ -20,7 +20,7 @@ use time::OffsetDateTime;
 use tokio::{
     join, spawn,
     sync::{mpsc, oneshot, Mutex, RwLock},
-    task::JoinHandle,
+    task::{block_in_place, JoinHandle},
     time::sleep,
 };
 
@@ -397,13 +397,14 @@ async fn execute_backfill_news(
     let predictions = join_all(inputs.chunks(app_config.max_bert_inputs).map(|inputs| {
         let sequence_classifier = app_config.sequence_classifier.clone();
         async move {
-            sequence_classifier
-                .lock()
-                .await
-                .predict(inputs.iter().map(String::as_str).collect::<Vec<_>>())
-                .into_iter()
-                .map(|label| Prediction::try_from(label).unwrap())
-                .collect::<Vec<_>>()
+            let sequence_classifier = sequence_classifier.lock().await;
+            block_in_place(|| {
+                sequence_classifier
+                    .predict(inputs.iter().map(String::as_str).collect::<Vec<_>>())
+                    .into_iter()
+                    .map(|label| Prediction::try_from(label).unwrap())
+                    .collect::<Vec<_>>()
+            })
         }
     }))
     .await