@Override
        public String toString() {
            return "DynamicSecurityHeaderCallCredentials [extraHeadersSupplier=" + this.extraHeadersSupplier + "]";
        }
The dynamic security header {@link CallCredentials} simply adds a set of dynamic headers to the call. Their
specific meaning is server specific. This implementation can be used, for example, for BasicAuth.
grpc-client-spring-boot-starter/src/main/java/net/devh/boot/grpc/client/security/CallCredentialsHelper.java