Explain the `compute` function vs custom Isolates.

compute is a high-level wrapper for spawning temporary Isolates, whereas custom Isolates offer sustained, bidirectional communication.

Using compute(function, data) spawns a background isolate, runs the function, returns the result to the main thread, and immediately kills the isolate. Spawning a custom Isolate.spawn() allows establishing persistent ReceivePort and SendPort connections for continuous data streaming and lower overhead across multiple calls.