@Override
    public boolean equals(@Nullable Object obj) {
        if (obj == this) {
            return true;
        }

        if (!(obj instanceof ServerPort)) {
            return false;
        }

        final ServerPort that = (ServerPort) obj;
        final int hashCode = this.hashCode;
        if (hashCode != 0 && that.hashCode != 0 && hashCode != that.hashCode) {
            return false;
        }

        return comparisonStr.equals(that.comparisonStr);
    }
Returns the port group this {@link ServerPort} belongs to, or {@code 0} if this {@link ServerPort}
doesn't belong to any port group.
core/src/main/java/com/linecorp/armeria/server/ServerPort.java