Function build_polkadot_syncing_strategy 

pub fn build_polkadot_syncing_strategy<Block, Client, Net>(
    protocol_id: ProtocolId,
    fork_id: Option<&str>,
    net_config: &mut FullNetworkConfiguration<Block, <Block as BlockT>::Hash, Net>,
    warp_sync_config: Option<WarpSyncConfig<Block>>,
    block_downloader: Arc<dyn BlockDownloader<Block>>,
    client: Arc<Client>,
    spawn_handle: &SpawnTaskHandle,
    metrics_registry: Option<&Registry>,
    archive_blocks: bool,
) -> Result<Box<dyn SyncingStrategy<Block>>, Error>
where
    Block: BlockT,
    Client: HeaderBackend<Block> + BlockBackend<Block> + HeaderMetadata<Block, Error = Error> + ProofProvider<Block> + Send + Sync + 'static,
    Net: NetworkBackend<Block, <Block as BlockT>::Hash>,

Build standard polkadot syncing strategy