import type { WorkItemAttachment } from "../work-items/attachments.js";
interface Derivative {
    path: string;
    mime: string;
    filename: string;
    /** Names the derivative in the ETag, so a variant switch is a cache miss. */
    variant: string;
    /** A derivative was asked for and could not be produced; serve uncached. */
    isFallback: boolean;
}
export interface AttachmentVariant extends Derivative {
    size: number;
}
/**
 * Resolve the file to stream for one attachment request. Returns null when a
 * poster was asked for and cannot be produced, because a poster URL that quietly
 * returned the whole video would be worse than a miss.
 */
export declare function selectAttachmentVariant(attachment: WorkItemAttachment, params: URLSearchParams, download: boolean): Promise<AttachmentVariant | null>;
export {};
//# sourceMappingURL=attachment-variants.d.ts.map