import okhttp3.Headers
import okhttp3.Request
import okhttp3.RequestBody
import okhttp3.internal.http.HttpMethod

fun Request.commonHeader(name: String): String? = headers[name]

fun Request.commonHeaders(name: String): List<String> = headers.values(name)

fun Request.commonNewBuilder(): Request.Builder = Request.Builder(this)

fun Request.commonCacheControl(): CacheControl {
  var result = lazyCacheControl

import okhttp3.internal.commonCacheResponse
import okhttp3.internal.commonClose
import okhttp3.internal.commonCode
import okhttp3.internal.commonEmptyResponse
import okhttp3.internal.commonHeader
import okhttp3.internal.commonHeaders
import okhttp3.internal.commonIsRedirect
import okhttp3.internal.commonIsSuccessful
import okhttp3.internal.commonMessage
import okhttp3.internal.commonNetworkResponse
import okhttp3.internal.commonNewBuilder

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()]):
    return headers
```