public String getId() {
        return id;
    }
Gets this ShapeLink's id.
Id is the artifact-specific identifier for the artifact component. For example, in Java a valid id
would be the fully-qualified name of a class, method, or field as defined in
<a href="https://docs.oracle.com/en/java/javase/11/docs/specs/doc-comment-spec.html"> Documentation Comment
Specification for the Standard Doclet</a>

@return this ShapeLink's id
smithy-codegen-core/src/main/java/software/amazon/smithy/codegen/core/trace/ShapeLink.java