var google.golang.org/grpc/internal/envconfig.ALTSMaxConcurrentHandshakes

one use

	google.golang.org/grpc/internal/envconfig (current package)
		envconfig.go#L46: 	ALTSMaxConcurrentHandshakes = uint64FromEnv("GRPC_ALTS_MAX_CONCURRENT_HANDSHAKES", 100, 1, 100)