Enum UserEvent 

pub(crate) enum UserEvent {
    Ready(Gpu),
    Failed(String),
    Command(Option<McpCommand>),
}

Events delivered to the winit loop from outside a WindowEvent.

Variants

Ready(Gpu)

The async GPU setup finished; the scene is built from it here, on the main thread.

Failed(String)

The async GPU setup failed; the message is reported and the app exits.

Command(Option<McpCommand>)

A command from the MCP transport, to run against a world of the host.

It arrives on this thread because a world is not Send; the app resolves the command’s world handle and dispatches it here, between frames, so no command ever runs while a frame is being drawn.

The command is wrapped in an Option because a user event reaches its callbacks mutably and the one that runs it takes it out.