const runtime.profWriteExtra

4 uses

	runtime (current package)
		profbuf.go#L114: 	profWriteExtra     profIndex = 1 << 33 // overflow or eof waiting
		profbuf.go#L411: 		new := old | profWriteExtra
		profbuf.go#L483: 		if bw&profWriteExtra != 0 {
		profbuf.go#L488: 			b.w.cas(bw, bw&^profWriteExtra)