Extracting First Element from Stream in TypeScript Code

const result = yield* pipe(
  usernameAuthorityService.setUsernamesFor(requests),
  Effect.andThen(
    flow(
      Stream.timeoutFail(() => new SetUsernameForSubmitTimeout({}), Duration.seconds(6)),
      Stream.tap(flow(
        logUsernameRegistrationEvent,
        Effect.annotateLogs({
          usernames: unregisteredUsernames.map(({ username }) => username),
        }),
      )),
      Stream.tap((event) => {
        if (event.type === 'txBestBlocksState' && !event.found) {
          return Effect.fail(new TransactionNotFoundInBestBlockError({ txHash: event.txHash }))
        }

        return Effect.void
      }),
      Stream.filter((event) => event.type === 'finalized'),
      Stream.map(Effect.succeed),
      Stream.catchAll(Effect.fail),
      Stream.run(Sink.head()),
      Effect.andThen(Effect.orDie),
      Effect.flatten
    ),
  ),
)