default boolean isSerial() {
        return false;
    }
Plugins can choose whether or not projections they are in can be run in
parallel with other projections.

<p>By default plugins allow parallel execution.</p>

@return Returns true if the plugin should be run serially, false if it
 can be run in parallel with other plugins.
smithy-build/src/main/java/software/amazon/smithy/build/SmithyBuildPlugin.java