@Test
    public void testExtensionsWithEqualValuesAreUnique() {
        // If the maps are distinct objects but have the same underlying values, the SaslExtension
        // objects should still be unique.
        assertNotEquals(new SaslExtensions(Collections.singletonMap("key", "value")),
            new SaslExtensions(Collections.singletonMap("key", "value")),
            "SaslExtensions with unique maps should be unique");

        // If the maps are the same object (with the same underlying values), the SaslExtension
        // objects should still be unique.
        assertNotEquals(new SaslExtensions(map),
            new SaslExtensions(map),
            "SaslExtensions with duplicate maps should be unique");

        // If the maps are empty, the SaslExtension objects should still be unique.
        assertNotEquals(SaslExtensions.empty(),
            SaslExtensions.empty(),
            "SaslExtensions returned from SaslExtensions.empty() should be unique");
    }
Tests that even when using the same underlying values in the map, two {@link SaslExtensions}
are considered unique.

@see SaslExtensions class-level documentation
clients/src/test/java/org/apache/kafka/common/security/SaslExtensionsTest.java