pass cqe->flags with MsgRingData (#248)

* pass flags in msg ring op code

* correct variable name

Author: bits0rcerer

src/opcode.rs

@@ -1453,9 +1453,9 @@ opcode! {
         sqe.len = result as u32;
         sqe.__bindgen_anon_1.off = user_data;
         sqe.__bindgen_anon_3.msg_ring_flags = opcode_flags;
-        if let Some(_flags) = user_flags {
-            // TODO(lucab): add IORING_MSG_RING_FLAGS_PASS support (in v6.3):
-            // https://lore.kernel.org/all/[email protected]/t/#u
+        if let Some(flags) = user_flags {
+            sqe.__bindgen_anon_5.file_index = flags;
+            unsafe {sqe.__bindgen_anon_3.msg_ring_flags |= sys::IORING_MSG_RING_FLAGS_PASS};
         }
         Entry(sqe)
     }