Macro near_contract_standards::impl_fungible_token_storage

macro_rules! impl_fungible_token_storage {
    ($contract : ident, $token : ident $(, $on_account_closed_fn : ident) ?) => { ... };
}

Ensures that when fungible token storage grows by collections adding entries, the storage is be paid by the caller. This ensures that storage cannot grow to a point that the FT contract runs out of Ⓝ. Takes name of the Contract struct, the inner field for the token and optional method name to call when the account was closed.