IDL consumers may need to reference the field names in code. To enable one definition for a field name, IDL should generate string constants for each field name in a class.

For a document like this

{
   "example" : "test"
}

A mockup of what the generated code could look like:

class Sample {
constexpr StringData kExampleField = "example";
}

The idea came from judah.schvimer for SERVER-28621.