Usage
external_evaluator(
  endpoint = getOption("tutorial.external.host",
    Sys.getenv("TUTORIAL_EXTERNAL_EVALUATOR_HOST", NA)),
  max_curl_conns = 50
)external_evaluator(
  endpoint = getOption("tutorial.external.host",
    Sys.getenv("TUTORIAL_EXTERNAL_EVALUATOR_HOST", NA)),
  max_curl_conns = 50
)