(string) Custom separator between metrics. Defaults to ' - '
overall_bar_format
(string format) Custom bar format for overall (outer) progress
bar, see https://github.com/tqdm/tqdm#parameters for more detail.
By default: 'l_barbar n_fmt/total_fmt ETA: remainings, rate_fmtpostfix'
epoch_bar_format
(string format) Custom bar format for epoch (inner) progress bar,
see https://github.com/tqdm/tqdm#parameters for more detail.
update_per_second
(int) Maximum number of updates in the epochs bar per second, this
is to prevent small batches from slowing down training. Defaults to 10.