feat: add native session handlers

src/plugin/native.rs

@@ -0,0 +1,16 @@
+use std::{ffi::{c_char, c_void}, os::raw::c_uint};
+
+/// The native returned value from librustdesk native.
+/// 
+/// [Note]
+/// The data is owned by librustdesk.
+#[repr(C)]
+pub struct NativeReturnValue{
+    return_type: c_uint,
+    data: *const c_void
+}
+
+pub(super) extern "C" fn cb_native_data(method: *const c_char, json: *const c_char, raw: *const c_void, raw_len: usize) -> NativeReturnValue {
+    // TODO: cb for native data.
+    return NativeReturnValue { return_type: 0, data: std::ptr::null() };
+}