+B<KTLSTxZerocopySendfile>: use the zerocopy TX mode of sendfile(), which gives
+a performance boost when used with KTLS hardware offload. Note that invalid TLS
+records might be transmitted if the file is changed while being sent. This
+option has no effect if B<KTLS> is not enabled. Equivalent to
+B<SSL_OP_ENABLE_KTLS_TX_ZEROCOPY_SENDFILE>. This option only applies to Linux.
+KTLS sendfile on FreeBSD doesn't offer an option to disable zerocopy and
+always runs in this mode.
+