feat: Add support of waitForMultipleEvents

[charanjit-singh]

Is your feature request related to a problem? Please describe.
Yes, I want to wait for 2 events and continue any of the two events is received. If no event is received then longest of both timeouts should hit and I should get null.

Describe the solution you'd like
want to wait for 2 events and continue any of the two events is received. If no event is received then longest of both timeouts should hit and I should get null.

Describe alternatives you've considered

Following code is not going to work because promises don't work in inngest as normal promises and are not allowed.

const waitForStampUploaded = async () => {
    return new Promise((resolve, reject) => {
        // Wait for 1000 ms
        setTimeout(() => {
            resolve({
                "data": {
                    "status": "success",
                }
            });
        }, 1000);
    });
}


const waitForStampSkipped = async () => {
    return new Promise((resolve, reject) => {
        // Wait for 1000 ms
        setTimeout(() => {
            resolve({
                "data": {
                    "status": "skipped",
                }
            })
        }, 1200);

        setTimeout(() => {
            resolve(null)
        }, 1000);
    });
}


const stampStatus = () => {
    // Wait for stampUploaded promise or stampSkipped promise
    // If any of the promise is resolved with not null value, return the value
    // If any of the promise is resolved with null value, wait for the other promise to 
    // Check if it is resolved with null value or not
    // If both are null then return null
    // If any of the promise is resolved with not null value, return the value
    // We must wait for both the promises to resolve in parallel


    return new Promise((resolve) => {   

        let stampUploadedPromise = waitForStampUploaded();
        let stampSkippedPromise = waitForStampSkipped();

        let isStampUploadedResolved = false;
        let isStampSkippedResolved = false;

        stampUploadedPromise.then((response) => {
            isStampUploadedResolved = true;
            if (response != null) {
                resolve(response);
            }
            else {
                if(isStampSkippedResolved) {
                    resolve(null);
                }
            }
        });

        stampSkippedPromise.then((response) => {
            isStampSkippedResolved = true;
            if (response != null) {
                resolve(response);
            } else {
                if(isStampUploadedResolved) {
                    resolve(null);
                }
            }
        });

    });

}


/**
--------------------------------
| success | skip | output |
--------------------------------
| 0       | 1    |  1     |
| 1       | 0    |  1     |
| 1       | 1    |  1     |
| 0       | 0    |  0     |
--------------------------------
 */

[linear]

INN-2982 feat: Add support of waitForMultipleEvents