What is strftime?

This is a Go library that formats dates and times using pattern strings, the kind of thing you'd use when you need to turn a date like "January 2, 2006" into a specific format like "2006-01-02" or "Mon 02 Jan" for display in your app or API. The library is built for speed, especially when you're using the same format pattern over and over. You set up the pattern once (say, %Y-%m-%d %H:%M:%S), and then reuse it many times without re-parsing that pattern every single time. Under the hood, it pre-compiles the pattern so formatting becomes really fast. The benchmarks show it's significantly faster than other Go date-formatting libraries, sometimes 3, 10x quicker depending on how you use it. The library supports a huge range of format codes, everything from %Y for the full year to %A for the full weekday name to %z for timezone offsets. You can also suppress leading zeros with a - flag (e.g., %-m gives "1" instead of "01"). If you need to output dates in another language, you can provide your own month and weekday names. There's even support for less common patterns like milliseconds (%L) or Unix timestamps (%s) that you can add yourself. You'd use this if you're building a web service, logging system, or any application where you format dates repeatedly, especially if performance matters. The library gives you flexibility too: you can write formatted dates to a file, a network connection, or just get back a string. The README doesn't claim to be a full tutorial, but the API is straightforward: create a formatter with New(), then call Format() or FormatString() as needed.