在FastAPI中请求上下文？

from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/")
async def get_request_headers(request: Request):
    headers = request.headers
    return headers

from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/items/{item_id}")
async def get_item(item_id: int, request: Request):
    return {"item_id": item_id}

from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/items/")
async def get_items(request: Request):
    query_params = request.query_params
    return query_params

from fastapi import FastAPI, Request

app = FastAPI()

@app.post("/items/")
async def create_item(request: Request):
    item = await request.json()
    return item