How to download a file in Streamlit?
Starting with v0.88, st.download_button is natively built into Streamlit. Check out the release notes, API, and a sample app.
Example usage
```python
import streamlit as st
Text files
text_contents = '''
Foo, Bar
123, 456
789, 000
'''
Different ways to use the API
st.download_button('Download CSV', text_contents, 'text/csv')
st.download_button('Download CSV', text_contents)  # Defaults to 'text/plain'
with open('myfile.csv') as f:
   st.download_button('Download CSV', f)  # Defaults to 'text/plain'
---
Binary files
binary_contents = b'whatever'
Different ways to use the API
st.download_button('Download file', binary_contents)  # Defaults to 'application/octet-stream'
with open('myfile.zip', 'rb') as f:
   st.download_button('Download Zip', f, file_name='archive.zip')  # Defaults to 'application/octet-stream'
