FairLane-Router

    async sendTransaction(wire) {      const result = await call('sendTransaction', [        // `btoa`, not `Buffer`: this module is in the web bundle too. A wire        // transaction is at most 1232 bytes, well within one spread.        btoa(String.fromCharCode(...wire)),        { encoding: 'base64', skipPreflight: true },      ])      const parsed = z.string().min(1).safeParse(result)      if (!parsed.success) throw new RpcError('sendTransaction: the result is not a signature')      return parsed.data    },     // `confirmed`, not the default `finalized`: a finalized blockhash is ~32    // slots old already, and that is time cut off the window both legs share.    async getLatestBlockhash() {      const result = await call('getLatestBlockhash', [{ commitment: 'confirmed' }])      const parsed = latestBlockhashSchema.safeParse(result)      if (!parsed.success) throw new RpcError('getLatestBlockhash: the result is not a blockhash')      return { ...parsed.data.value, slot: parsed.data.context.slot }    },     async getBlockHeight() {      const result = await call('getBlockHeight', [{ commitment: 'confirmed' }])      const parsed = slotSchema.safeParse(result)

1. Line 349 async sendTransaction(wire) {: Submits the signed transaction to the cluster.
2. Line 363 async getLatestBlockhash() {: Fetches a recent blockhash. Transactions expire if it gets too old.