in api_generator/src/generator/code_gen/request/request_builder.rs [771:782]
fn create_default_fields(default_fields: &[&syn::Ident]) -> Vec<FieldValue> {
default_fields
.iter()
.filter(|&&part| part != &ident("headers"))
.map(|part| syn::FieldValue {
attrs: vec![],
ident: ident(part),
expr: syn::ExprKind::Path(None, path_none(ident("None").as_ref())).into(),
is_shorthand: false,
})
.collect()
}