sysvarRecentBlockhashesPubkey top-level property
The RecentBlockhashes sysvar contains the active recent blockhashes as well as their associated fee calculators. It is updated every slot. Entries are ordered by descending block height, so the first entry holds the most recent block hash, and the last entry holds an old block hash.
Implementation
final Pubkey sysvarRecentBlockhashesPubkey = Pubkey.fromBase58(
'SysvarRecentB1ockHashes11111111111111111111',
);