Macro near_primitives::checked_feature

macro_rules! checked_feature {
    ("stable", $feature : ident, $current_protocol_version : expr) => { ... };
    ($feature_name : tt, $feature : ident, $current_protocol_version : expr) => { ... };
    ($feature_name : tt, $feature : ident, $current_protocol_version : expr,
 $feature_block : block) => { ... };
    ($feature_name : tt, $feature : ident, $current_protocol_version : expr,
 $feature_block : block, $non_feature_block : block) => { ... };
}