My take: Like with any interface the definer needs to balance api user ergonomics, your developer's ergonomics, and internal developer's needs. If your api can

My take: Like with any interface the definer needs to balance api user ergonomics, your developer's ergonomics, and internal developer's needs. If your api can get a little toe-hold on the remote side there's all sorts of advantages (and compromises) you can leverage. In this case that means the api designer gets a little bit of wiggle room in the process userspace where it might be more appropriate to say shim some calls so that they're no longer 1:1 with a syscall. The obvious example is that malloc() can call syscalls for you and is the "default" way to allocate memory you might want to provide but It's more of it's own little runtime. My favorite example was in my time at LinkedIn. Because the internal Kafka team had thick client libraries, making the company wide change to enable encryption was as simple as pushing out new libraries and deprecating old ones.