private String contrast() {
        final RoleDO before = (RoleDO) getBefore();
        Objects.requireNonNull(before);
        final RoleDO after = (RoleDO) getAfter();
        Objects.requireNonNull(after);
        if (Objects.equals(before, after)) {
            return "it no change";
        }
        final StringBuilder builder = new StringBuilder();
        if (!Objects.equals(before.getRoleName(), after.getRoleName())) {
            builder.append(String.format("name[%s => %s] ", before.getRoleName(), after.getRoleName()));
        }
        if (!Objects.equals(before.getDescription(), after.getDescription())) {
            builder.append(String.format("disc[%s => %s] ", before.getDescription(), after.getDescription()));
        }
        return builder.toString();
    }
Create a new {@code RoleChangedEvent}.operator is unknown.

@param source   Current role state
@param before   Before the change role state
@param type     event type
@param operator operator
shenyu-admin/src/main/java/org/apache/shenyu/admin/model/event/role/RoleChangedEvent.java