Describe the bug

When using simple cache adapters MaxListenersExceededWarning is emitted. This has previously been investigated in #792 and #1128 but either it is a regression or did not account for highly asynchronous environments with 100's of parallel requests.

Unsure if this is best opened in either keyv or cacheable-request, but given it was declared solved in #1128 I've opened it here first.

Environment Info:
  System:
    OS: macOS 10.15.7
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 12.19.0 - ~/.nvm/versions/node/v12.19.0/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 6.14.8 - ~/.nvm/versions/node/v12.19.0/bin/npm
  Browsers:
    Chrome: 86.0.4240.198
    Safari: 14.0

Got: 11.8.0

Actual behavior

MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added to [Keyv]. Use emitter.setMaxListeners() to increase limit

Code to reproduce

const got = require('got');

const client = got.extend({
    cache: {
        get: (key) => {
            return undefined;
        },
        set: (key, value) => {

        }
    }
});

(async () => {
    const promises = [];

    for (let i = 0; i < 20; i++) {
        promises.push(client('https://www.google.com', { method: 'HEAD' }));
    };

    await Promise.all(promises);

    console.log('Done');
})();

Checklist

• I have read the documentation.
• I have tried my code with the latest version of Node.js and Got.

Related Tickets

https://github.com/lukechilds/cacheable-request/issues/97