The socket library in util/net/sock.cpp provides failpoints for calls into its send and recv methods. However, when enabled, these failpoints do not actually prevent the syscall from executing: they only cause the return value of the send or recv syscall to be ignored and force a branch into the error handling logic.

This makes the failpoints potentially not useful: A test trying to use the failpoints to simulate a network partition, for instance, would see a socket error in the caller, but the intended recipient would actually see the sent data.

When enabled, the socket send/recv failpoints should inhibit data transfer.