termio: use DerivedConfig

src/termio/message.zig

@@ -3,6 +3,7 @@ const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const renderer = @import("../renderer.zig");
 const terminal = @import("../terminal/main.zig");
+const termio = @import("../termio.zig");
 
 /// The messages that can be sent to an IO thread.
 ///
@@ -28,6 +29,9 @@ pub const Message = union(enum) {
         padding: renderer.Padding,
     };
 
+    /// The derived configuration to update the implementation with.
+    change_config: termio.Impl.DerivedConfig,
+
     /// Resize the window.
     resize: Resize,