default void scheduleBatch(Stream<TaskInstance<?>> taskInstances, Instant executionTime) {
    StreamUtils.chunkStream(taskInstances, DEFAULT_BATCH_SIZE)
        .forEach(chunk -> scheduleBatch(chunk, executionTime));
  }
Schedule a batch of executions. If any of the executions already exists, the scheduling will
fail and an exception will be thrown.

@param taskInstances Task-instances to schedule, optionally with data
@param executionTime Instant it should run
@see java.time.Instant
@see com.github.kagkarlsson.scheduler.task.TaskInstance
db-scheduler/src/main/java/com/github/kagkarlsson/scheduler/SchedulerClient.java