This is for the curious that learn by doing...
As admin add a Server Method in C#.
Name: _Hello_World
Content:
// Testing return to PostMan with route: /method._Hello_World Innovator inn = this.getInnovator(); return inn.newResult("Hello World!");
In PostMan obtain a token (not covered here) and add new "POST" request that will use it in Authorization tab:
Point to your server and tack-on /server/odata/method._Hello_Word:
You should see a return of "Hello World".
Here is the resultant curl equivalent:
curl --location --request POST 'localhost/.../method._Hello_World' \
--header 'Authorization: Bearer.NOT_PASTING_IS_SO_BIG' \
--data-raw ''