added the fast tokenizer

app.py

@@ -14,7 +14,7 @@ app = FastAPI(
 class ContactDetector:
     def __init__(self):
         cache_dir = "/app/model_cache"
-        self.tokenizer = RobertaTokenizer.from_pretrained('roberta-base', cache_dir=cache_dir)
+        self.tokenizer = RobertaTokenizer.from_pretrained('roberta-base', use_fast=True, cache_dir=cache_dir)
         self.model = RobertaForSequenceClassification.from_pretrained('roberta-base', num_labels=2, cache_dir=cache_dir)
         self.device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
         self.model.to(self.device)