@Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj == null || obj.getClass() != this.getClass()) {
            return false;
        }
        Deprecated that = (Deprecated) obj;
        return Objects.equals(this.message, that.message)
                && Objects.equals(this.since, that.since);
    }
Gets the deprecated since value.

@return returns the optional deprecated since value.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/syntax/parameters/Deprecated.java