Constant GPU_TIMEOUT_MESSAGE 

pub const GPU_TIMEOUT_MESSAGE: &'static str;

The message every GPU wait timeout carries, so a host that sees only error text can still classify it: one sentence for the renderer, the native interop helpers, and encoder inputs alike. The sentence every wait on GPU work that timed out carries, wherever it was waited on (the renderer, a native interop helper, an encoder input), so a host that sees only error text tells a hung GPU from a generic failure. Hosts classify it as GPU_TIMEOUT.