@Test
@DisplayName("protobufKeyToHexIfEd25519OrNull threshold key")
public void protobufKeyToHexIfEd25519OrNull_ThresholdKey() throws Exception {

    var ks = "0011223344556677889900aabbccddeeff0011223344556677889900aabbccddeeff";
    var key = Key.newBuilder().setEd25519(ByteString.copyFrom(Hex.decodeHex(ks))).build();
    var keyList = KeyList.newBuilder().addKeys(key).build();
    var tk = ThresholdKey.newBuilder().setThreshold(1).setKeys(keyList).build();
    var input = Key.newBuilder().setThresholdKey(tk).build();
    var result = Utility.protobufKeyToHexIfEd25519OrNull(input.toByteArray());
    assertThat(result).isNull();
}