egui-wgpu: reduce input latency by defaulting to double-buffering #8350

Job	Run time
android	25s
Check wasm32 + wasm-bindgen	3m 8s
Format + check + test	5m 15s
cargo-deny aarch64-apple-darwin	41s
cargo-deny aarch64-linux-android	46s
Check Windows	1m 26s
cargo-deny i686-pc-windows-gnu	45s
cargo-deny i686-pc-windows-msvc	39s
cargo-deny i686-unknown-linux-gnu	42s
cargo-deny wasm32-unknown-unknown	40s
cargo-deny x86_64-apple-darwin	38s
cargo-deny x86_64-pc-windows-gnu	38s
cargo-deny x86_64-pc-windows-msvc	49s
cargo-deny x86_64-unknown-linux-gnu	47s
cargo-deny x86_64-unknown-linux-musl	38s
cargo-deny x86_64-unknown-redox	50s
	18m 47s

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