Asynchronously triggering a Custom API action from a plugin

Hi all,

I'm attempting to update a plugin that's currently timeing out when running a Custom Api action repeatedly for different entities. Right now the only way I can do this is using an external program to trigger the actions asynchronously, but I'd like to get this running from within a plugin.

I've already tried using the ExecuteAsyncRequest class, but this doesn't seem to work with custom API requests, and the ExecuteMultipleRequest class, which forces you to wait until all requests are finished.

I don't need to read the responses once the jobs are started as the results are logged elsewhere, and the order the requests are executed in don't matter.