File

net.http: Send entire HTTP request header as one write When opportunistic writes are enabled this reduces the number of syscalls and TCP packets sent on the wire. Experiments with TCP Fast Open made this even more obvious. That table trick probably wasn't as efficient. Lua generates bytecode for a table with zero array slots and space for two entries in the hash part, plus code to set [2] and [4]. I didn't verify but I suspect it would have had to resize the table when setting [1] and [3], although probably only once. Concatenating the strings directly in Lua is easier to read and involves no extra table or function call.

Thanks for your interest in contributing to the project!

There are many ways to contribute, such as helping improve the
documentation, reporting bugs, spreading the word or testing the latest
development version.

You can find more information on how to contribute at <https://prosody.im/doc/contributing>

See also the HACKERS and README files.