public static Argon2Hash generate(String algorithmName, ByteSource source, ByteSource salt, int iterations) {
        return generate(algorithmName, DEFAULT_ALGORITHM_VERSION, source, salt, iterations,
                DEFAULT_MEMORY_KIB, DEFAULT_PARALLELISM, DEFAULT_OUTPUT_LENGTH_BITS);
    }
128 bits of salt is the recommended salt length, taken from draft-irtf-cfrg-argon2-13, 4.2.
crypto/support/hashes/argon2/src/main/java/org/apache/shiro/crypto/support/hashes/argon2/Argon2Hash.java