wait_until_step.This hook delays execution until global step reaches to wait_until_step. It
is used to gradually start workers in distributed settings. One example usage
would be setting wait_until_step=int(K*log(task_id+1)) assuming that
task_id=0 is the chief.
hook_global_step_waiter(wait_until_step)An integer indicating that until which global step should we wait.
Other session_run_hook wrappers: hook_checkpoint_saver,
hook_history_saver,
hook_logging_tensor,
hook_nan_tensor,
hook_progress_bar,
hook_step_counter,
hook_stop_at_step,
hook_summary_saver,
session_run_hook