Move model initialization to separate thread.

Initializing the model in main thread slows down the loading of
streamlit application, so initialize it from the thread.

app.py

@@ -1,10 +1,15 @@
 import streamlit as st
 
 from model import predictor
+from streamlit.scriptrunner import add_script_run_ctx
 import audiobot
 import chatbot
 import os
+import threading
 
+def runInThread():
+    print('Initialize model in thread')
+    st.session_state['predictor'] = predictor.Predictor()
 
 def run():
     st.set_page_config(
@@ -14,7 +19,6 @@ def run():
     )
 
     os.environ['TOKENIZERS_PARALLELISM'] = 'false'
-    st.session_state['predictor'] = predictor.Predictor()
 
     st.sidebar.title('VQA Bot')
     st.sidebar.write('''
@@ -35,5 +39,9 @@ def run():
         '[Github](https://github.com/msak1612/vqa_chatbot)'
     )
 
+    if 'predictor' not in st.session_state:
+        thread = threading.Thread(target=runInThread)
+        add_script_run_ctx(thread)
+        thread.start()
 
 run()

chatbot.py

@@ -47,8 +47,8 @@ def show():
             image = Image.open(upload_pic)
             st.image(upload_pic, use_column_width='auto')
         else:
-            st.session_state.question.clear()
-            st.session_state.answer.clear()
+            st.session_state.question=[]
+            st.session_state.answer=[]
             st.session_state.input = ''
     with text_col:
         input = st.text_input('', '', key='input')