Function fc_rpc::frontier_backend_client::native_block_id

pub fn native_block_id<B: BlockT, C>(
    client: &C, 
    backend: &Backend<B>, 
    number: Option<BlockNumber>
) -> RpcResult<Option<BlockId<B>>> where
    B: BlockT,
    C: HeaderBackend<B> + 'static,
    B: BlockT<Hash = H256> + Send + Sync + 'static,
    C: Send + Sync + 'static,