Created a python fastapi endpoint – post which takes a pdf file as input does some processing and returns the pdf file back

from fastapi import FastAPI, status, File, Response

app = FastAPI()


@app.post("/get_file") 
def create_item(file_name: str, file_bytes:bytes = File(...)):
   # process the file
   processed_file_bytes = process(file_bytes)
   headers = {'Content-Disposition': 'inline; filename="out.pdf"'}
   return Response(processed_file_bytes, headers=headers, media_type='application/pdf')

this works fine when testing via swagger docs

But when I try to test it using requests

import requests
import fitz

file_name = 'sample.pdf'
file_bytes = fitz.open(file_name).tobytes()

payload = {'file_name':file_name, 'file_bytes':file_bytes}

r = requests.post("http://localhost:8000/get_file", params = payload)

Error:

ConnectionError: Connection Aborted. [Errno 10054] An existing connection was forcibly 
closed by the remote host, None, 10054, None

Any suggestion will be helpful.