Function export_tokens_internal 

pub fn export_tokens_internal<T: Into<TokenStream>, E: Into<TokenStream>>(
    attr: T,
    tokens: E,
    emit: bool,
    hide_exported_ident: bool,
) -> Result<TokenStream>

The internal code behind the #[export_tokens] attribute macro.

The attr variable contains the tokens for the optional naming Ident (necessary on Items that don’t have an inherent Ident), and the tokens variable is the tokens for the Item the attribute macro can be attached to. The attr variable can be blank tokens for supported items, which include every valid syn::Item except for syn::ItemForeignMod, syn::ItemUse, syn::ItemImpl, and Item::Verbatim, which all require attr to be specified.

An empty TokenStream2 is sufficient for opting out of using attr

The hide_exported_ident variable specifies whether the macro uses an auto-generated name via export_tokens_macro_ident or the name of the item itself.