How many requests the batched path (see perform_many() and its
cached counterparts) actually sent, how many of those were a retry pass
rather than the first attempt, and how many came back rate limited,
since the process started or the last transport_stats_reset().
Value
A data frame with one row per host: host, dispatched,
retried, rate_limited. Zero rows when nothing has dispatched yet.
Examples
transport_stats_reset()
transport_stats()
#> [1] host dispatched retried rate_limited
#> <0 rows> (or 0-length row.names)