Message channel becomes a performance bottleneck under heavy messages rate. See #767.

Shared array buffer can act as a shared memory for worker-threads but is not friendly to manipulate.
Cluster worker does not offer a similar feature.

To implement it right, an encapsulation needs to be done exposing the same high-level API at the pool level:

class Shm {
    get(key)
    set(key, value)
    delete(key)
}

The set/get ops can be thread-safe or not (use atomics or mutex or semaphore), depending on the use case requirements
Pool expose a public property to access it
Task functions can import and use it to share structured-cloneable writable data?