libmongocrypt should follow the HTTP/1.1 spec and use CRLF newlines instead of LF:

Although the line terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single LF as a line terminator and ignore any preceding CR.

While currently the servers it communicates with may not make use of the fact that this is merely a "MAY" requirement that they can disregard, libmongocrypt should be future-proof and anticipate that servers could reject LF as a single line terminator in the future.

Node.js just started doing so, with the effect of breaking the mongosh test suite for libmongocrypt requests, citing CVE-2022-32213 (details not yet available at time of writing) as the reason.