The name of the function is SetLoadFromUrlHeader().
This may be what you need if the API requires a header.
SetLoadFromURLHeader('Content-Type','application/json')curl -X POST --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic dGZsbzA2YzpMTGJCUnYyTFNkTnJUdkZlbG85M2VnPT0=' -d '
SetLoadFromURLHeader('Accept','application/json')
SetLoadFromURLHeader('Authorization','Basic')
LoadFromUrl(cUrl)