402lab

  sessionAddress: string;  amount: AtomicAmount;}; /** * Builds and sends a devnet USDC TransferChecked from the human's wallet to the * agent's session wallet, creating the session's associated token account first * if it does not exist yet. Returns the base58 transaction signature for a * Solscan link. */export const fundSessionWallet = async ({  humanSigner,  sessionAddress,  amount,}: FundSessionInput): Promise<string> => {  const owner = address(sessionAddress);  const [{ value: latestBlockhash }, createSessionAta, source, destination] = await Promise.all([    solanaRpc.getLatestBlockhash().send(),    getCreateAssociatedTokenIdempotentInstructionAsync({ payer: humanSigner, owner, mint }),    associatedTokenAccount(humanSigner.address),    associatedTokenAccount(owner),  ]);   const transferChecked = getTransferCheckedInstruction({

1. Line 42 * Builds and sends a devnet USDC TransferChecked from the human's wallet to the: A checked token transfer, which also verifies the mint and decimals.
2. Line 54 solanaRpc.getLatestBlockhash().send(),: Fetches a recent blockhash. Transactions expire if it gets too old.

 const COMMITMENT = 'confirmed';const RPC_TIMEOUT_MS = 15_000; /** The `SolanaChain`/`DevnetChain` used by the split worker, reconciliation job and demo * on-ramp. A call past the timeout rejects, failing the split round instead of hanging it. */export const createSolanaChain = (rpcUrl: string, timeoutMs = RPC_TIMEOUT_MS): DevnetChain => {  const rpc = createSolanaRpc(rpcUrl);  const deadline = () => ({ abortSignal: AbortSignal.timeout(timeoutMs) });   return {    latestBlockhash: async () =>      (await rpc.getLatestBlockhash({ commitment: COMMITMENT }).send(deadline())).value,    send: async (transaction) => {      await rpc        .sendTransaction(getBase64EncodedWireTransaction(transaction), {          encoding: 'base64',          preflightCommitment: COMMITMENT,          skipPreflight: false,        })        .send(deadline());    },    // Without the history search a status older than the RPC's recent cache reads as null,    // which would let reconciliation release a batch that did pay out.

1. Line 49 (await rpc.getLatestBlockhash({ commitment: COMMITMENT }).send(deadline())).value,: Fetches a recent blockhash. Transactions expire if it gets too old.
2. Line 52 .sendTransaction(getBase64EncodedWireTransaction(transaction), {: Submits the signed transaction to the cluster.