function parseWorkflowRequest(request): Promise<WorkflowRequestParams>;

function parseWorkflowRequest(request): Promise<WorkflowRequestParams>;

POST: async ({ request }) => {
  const params = await parseWorkflowRequest(request)
  if (params.abort && params.runId) {
    // ...host-specific abort plumbing
    return new Response(null, { status: 204 })
  }
  const stream = runWorkflow({ workflow, runStore, ...params })
  return toServerSentEventsResponse(stream)
}

POST: async ({ request }) => {
  const params = await parseWorkflowRequest(request)
  if (params.abort && params.runId) {
    // ...host-specific abort plumbing
    return new Response(null, { status: 204 })
  }
  const stream = runWorkflow({ workflow, runStore, ...params })
  return toServerSentEventsResponse(stream)
}