Access to process full request object inside External Task Worker

Scenario:
I have a process that’s invoked by calling a REST end point. In turn an External Task Worker is executed. I can access the Process variable from inside Worker that were supplied in process request to REST Engine.

Questions:
How can I access all request headers from inside External Task Worker that were present in the process REST request sent to REST engine.

Even better how can I access the entire HTTP request object itself from inside External Task Worker that would automatically containing all process variables as well.