<chrono>: Reduce put_time calls in [time.format] #1900

Activity

1. Miya Natsuhara (mnatsuhara)

   changed the title [-]@statementreply [observes](https://github.com/microsoft/STL/pull/1870#discussion_r617528729) that the current `[time.format]` implementation calls `put_time` once for each formatting field - we should investigate improving performance here (perhaps by leveraging internal machinery).[/-] [+]<chrono>: Reduce `put_time` calls in `[time.format]`[/+] on May 4, 2021
2. Miya Natsuhara (mnatsuhara)

   added

   chronoC++20 chronoC++20 chrono

   performanceMust go fasterMust go faster

   on May 4, 2021