async previewEmail(post, newsletter, segment) {
        const exampleMember = await this.getExampleMember(null, segment);

        const subject = this.#emailRenderer.getSubject(post);
        let {html, plaintext, replacements} = await this.#emailRenderer.renderBody(post, newsletter, segment, {clickTrackingEnabled: false});

        return {
            subject,
            html: this.replaceDefinitions(html, replacements, exampleMember),
            plaintext: this.replaceDefinitions(plaintext, replacements, exampleMember)
        };
    }
@param {*} post
@param {*} newsletter
@param {import('./EmailRenderer').Segment} segment
@returns {Promise<{subject: string, html: string, plaintext: string}>} Email preview