static byte[] kemSuiteId(byte[] kemId) throws GeneralSecurityException {
    return Bytes.concat(KEM, kemId);
  }
Generates KEM suite id from {@code kemId} according to the definition in
https://www.rfc-editor.org/rfc/rfc9180.html#section-4.1-5. Only used for KEM suite id.

@throws GeneralSecurityException when byte concatenation fails.
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/HpkeUtil.java