@Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("BulkheadConfig{");
        sb.append("maxConcurrentCalls=").append(maxConcurrentCalls);
        sb.append(", maxWaitDuration=").append(maxWaitDuration);
        sb.append(", writableStackTraceEnabled=").append(writableStackTraceEnabled);
        sb.append(", fairCallHandlingEnabled=").append(fairCallHandlingEnabled);
        sb.append('}');
        return sb.toString();
    }
@Test
    public void testToString() {
        int maxConcurrent = 66;
        long maxWait = 555;

        BulkheadConfig config = BulkheadConfig.custom()
            .maxConcurrentCalls(maxConcurrent)
            .maxWaitDuration(Duration.ofMillis(maxWait))
            .writableStackTraceEnabled(false)
            .fairCallHandlingStrategyEnabled(false)
            .build();

        String result = config.toString();
        assertThat(result).startsWith("BulkheadConfig{");
        assertThat(result).contains("maxConcurrentCalls=66");
        assertThat(result).contains("maxWaitDuration=PT0.555S");
        assertThat(result).contains("writableStackTraceEnabled=false");
        assertThat(result).contains("fairCallHandlingEnabled=false");
        assertThat(result).endsWith("}");
    }