public void directedCodegen(DirectedCodegen<C, S, I> directedCodegen) {
        this.directedCodegen = directedCodegen;
    }
Sets the required {@link DirectedCodegen} implementation to invoke.

@param directedCodegen Directed code generator to run.
smithy-codegen-core/src/main/java/software/amazon/smithy/codegen/core/directed/CodegenDirector.java