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我试图让 Cloudflare 的工作人员跟踪一些 ERC20 代币的流通，作为学习 web3 和 wasm 的练习。认为它可能很简单，但到目前为止，大约 90% 的时间都在尝试解决这个难以捉摸的错误

A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from JavaScript to resolve but has detected that the Promise cannot possibly ever resolve because all code and events related to the Promise's request context have already finished.

我在网上寻找更多信息，但似乎我的错误来自不同的类型（？）。

这是一个简单的代码片段来重现。

mod erc20_abi;

use erc20_abi::ERC20_ABI;

use cfg_if::cfg_if;

use ethers::{
    contract::Contract,
    core::{abi::Abi, types::Address},
    prelude::{AbiError, U256},
    providers::{Http, Provider},
};
use num_format::{Locale, ToFormattedString};
use std::convert::TryFrom;
use wasm_bindgen::prelude::*;
cfg_if! {
    // When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
    // allocator.
    if #[cfg(feature = "wee_alloc")] {
        extern crate wee_alloc;
        #[global_allocator]
        static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
    }
}

#[wasm_bindgen]
pub async fn handle() -> String {

    let web3_ethereum = Provider::<Http>::try_from(WEB3_URL_ETHEREUM).unwrap();

    let abi: Abi = serde_json::from_str(ERC20_ABI).unwrap();

    let token_contract_ethereum = Contract::new(parse_address(ADDRESS_ETH), 
    abi, web3_ethereum);

    let convert_wei_to_decimal = |bignumber: U256| -> String {
        (bignumber.as_u128() / u128::pow(10, 18)).to_formatted_string(&Locale::en)
    };

    // I believe this is the problem, since just returning a String works fine.
    let total_supply_ethereum = token_contract_ethereum
        .method::<_, U256>("totalSupply", ())
        .unwrap()
        .call()
        .await
        .unwrap();


    convert_wei_to_decimal(total_supply_ethereum)
}

fn parse_address(address: &str) -> Address {
    address.parse::<Address>().unwrap()
}

这是 worker/workers.js 文件

addEventListener('fetch', (event) => {
    event.respondWith(handleRequest(event.request))
})

const { handle } = wasm_bindgen;
const instance = wasm_bindgen(wasm);
/**
 * Fetch and log a request
 * @param {Request} request
 */
async function handleRequest(request) {
    await instance;
    const output = await handle();
    let res = new Response(output, { status: 200 });
    res.headers.set('Content-type', 'text/html');
    return res;
}

货运.toml

[package]
name = "circulating-supply"
version = "0.1.0"
license = "GPL-3.0-or-later"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[lib]
crate-type = ["cdylib", "rlib"]

[profile.release]
opt-level = 's'  # Optimize for size.
lto = true
panic = "abort"
codegen-units = 1

[dependencies]
ethers = { git = "https://github.com/gakonst/ethers-rs" }
serde_json = "1.0.68"
num-format = "0.4.0"
cfg-if = "1.0.0"
wee_alloc = { version = "0.4.5", optional = true }
wasm-bindgen = "0.2.78"
wasm-bindgen-futures = "0.4.28"
js-sys = "0.3.55"

wrangler dev会很好地编译它，但是http://127.0.0.1:8787会导致Error 1101

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