public void flushWriters() {
        for (Map.Entry<String, T> entry : getWriters().entrySet()) {
            fileManifest.writeFile(entry.getKey(), entry.getValue().toString());
        }

        writers.clear();
    }
Writes each pending {@code CodegenWriter} to the {@link FileManifest}.

<p>The {@code toString} method is called on each writer to generate
the code to write to the manifest.

<p>This method clears out the managed {@code CodegenWriter}s, meaning a
subsequent call to {@link #getWriters()} will return an empty map.

<p>This method may be overridden as needed.
smithy-codegen-core/src/main/java/software/amazon/smithy/codegen/core/writer/CodegenWriterDelegator.java