Stackoverflow

{
  "checkedAt": "2026-10-14T07:00:58.241Z",
  "query": {
    "accepted": true,
    "q": "rust async trait",
    "tagged": "rust"
  },
  "questions": [
    {
      "accepted": true,
      "acceptedAnswer": "How can this desugar be done if no Future trait is imported? \n \n The compiler desugars to the fully-qualified path: core::future::Future . \n \n why is the Future trait not defined in Rust itself, but instead is in a crate? \n \n It is in the standard library: std::future::Future . The Rust API documentation has a search function; I encourage you to become familiar with it. \n The Future trait was defined in the futures crate before it was added to the standard library, much like the Stream trait. Those both exist in the standard library now.",
      "answers": 1,
      "license": "CC BY-SA 4.0, Stack Overflow",
      "link": "https://stackoverflow.com/questions/66859270/can-a-rust-async-function-work-without-importing-the-future-trait",
      "score": -1,
      "tags": [
        "rust",
        "future"
      ],
      "title": "Can a Rust async function work without importing the Future trait?"
    },
    {
      "accepted": true,
      "acceptedAnswer": "You've declared init to take 2 generic parameters: T and E . \n This means that the code that calls init has to provide the concrete types to fill in those parameters. For example, if someone was using your library, it would be totally feasible for them to write init::<i64, ()>() , and your code should deal with that. \n Because of that, when you define your impl DB for FavouritesDB , you write this: \n\nasync fn init<FavoritesDB, FavoritesError>() -> Result<FavoritesDB, FavoritesError>\n\n This is no different to writing: \n\nasync fn init<T, E>() -> Result<T, E>\n\n you've just given the type paramete",
      "answers": 1,
      "license": "CC BY-SA 4.0, Stack Overflow",
      "link": "https://stackoverflow.com/questions/70995999/generic-async-trait-that-returns-the-implemented-struct",
      "score": 0,
      "tags": [
        "rust"
      ],
      "title": "Generic async trait that returns the implemented Struct"
    }
  ],
  "source": "https://api.stackexchange.com/2.3/search/advanced"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://api.sitecheck-api.workers.dev/api/stackoverflow?accepted=true&answers=1&limit=2&q=rust+async+trait&tagged=rust'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://api.sitecheck-api.workers.dev/api/stackoverflow?accepted=true&answers=1&limit=2&q=rust+async+trait&tagged=rust' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.001 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.001" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.001 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.sitecheck-api.workers.dev%2Fapi%2Fstackoverflow
const res = await pay("https://api.sitecheck-api.workers.dev/api/stackoverflow?accepted=true&answers=1&limit=2&q=rust+async+trait&tagged=rust");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.001 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.001"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://api.sitecheck-api.workers.dev/api/stackoverflow?accepted=true&answers=1&limit=2&q=rust+async+trait&tagged=rust")
    print(res.status_code, res.text)