private static String[] filterFromCipherSuites(String[] cipherSuites, Set<String> toRemove) {
        if (cipherSuites == null || cipherSuites.length == 0) {
            return cipherSuites;
        }
        ArrayList<String> newCipherSuites = new ArrayList<>(cipherSuites.length);
        for (String cipherSuite : cipherSuites) {
            if (!toRemove.contains(cipherSuite)) {
                newCipherSuites.add(cipherSuite);
            }
        }
        return newCipherSuites.toArray(EMPTY_STRING_ARRAY);
    }
Returns X.509 key manager or null for none.
common/src/main/java/org/conscrypt/SSLParametersImpl.java