When `false`, instead of stopping when a promise rejects, it will wait for all the promises to settle and then reject with an [aggregated error](https://github.com/sindresorhus/aggregate-error) containing all the errors from the rejected promises.
Caveat: When `true`, any already-started async mappers will continue to run until they resolve or reject. In the case of infinite concurrency with sync iterables, *all* mappers are invoked on startup and will continue after the first rejection. [Issue #51](https://github.com/sindresorhus/p-map/issues/51) can be implemented for abort control.
@param input - Synchronous or asynchronous iterable that is iterated over concurrently, calling the `mapper` function for each element. Each iterated item is `await`'d before the `mapper` is invoked so the iterable may return a `Promise` that resolves to an item. Asynchronous iterables (different from synchronous iterables that return `Promise` that resolves to an item) can be used when the next item may not be ready without waiting for an asynchronous process to complete and/or the end of the iterable may be reached after the asynchronous process completes. For example, reading from a remote queue when the queue has reached empty, or reading lines from a stream.
@param mapper - Function which is called for every item in `input`. Expected to return a `Promise` or value.
@returns A `Promise` that is fulfilled when all promises in `input` and ones returned from `mapper` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `mapper` in `input` order.