grpc/ttnctx/context.go
func OutgoingContextWithKey(ctx context.Context, key string) context.Context {
	return outgoingContextWithMergedMetadata(ctx, "key", key)
}
func OutgoingContextWithKey(ctx context.Context, key string) context.Context {
	return outgoingContextWithMergedMetadata(ctx, "key", key)
}
// OutgoingContextWithKey returns an outgoing context with the key