pkg bufio, const MaxScanTokenSize ideal-int
pkg bufio, func NewScanner(io.Reader) *Scanner
pkg bufio, func ScanBytes([]uint8, bool) (int, []uint8, error)
pkg bufio, func ScanLines([]uint8, bool) (int, []uint8, error)
pkg bufio, func ScanRunes([]uint8, bool) (int, []uint8, error)
pkg bufio, func ScanWords([]uint8, bool) (int, []uint8, error)
pkg bufio, method (*Reader) WriteTo(io.Writer) (int64, error)
pkg bufio, method (*Scanner) Bytes() []uint8

```python
from typing import Annotated

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):