Check the scripting index, or use show properties. It looks like there are only two getters of interest before the send:
myAPIURL = "https://my.api.url/";
myRequest = New HTTP Request(
URL(myAPIURL),
Method("GET"),
Headers("username: XXX1234567");
);
showproperties(myRequest);
myRequest<<get last url; // "https://my.api.url/"
myRequest<<get method; // "GET"
Craige