/**
 * WebKitGTK (2.50) lacks ReadableStream.prototype[Symbol.asyncIterator], which pdf.js uses in
 * getTextContent. Installs a minimal version when it is missing; a no-op elsewhere.
 */
export function installStreamAsyncIterator(): void {
  const proto = (globalThis as { ReadableStream?: { prototype: object } }).ReadableStream?.prototype as
    | Record<symbol, unknown>
    | undefined;
  if (!proto || Symbol.asyncIterator in proto) return;
  proto[Symbol.asyncIterator] = function (this: ReadableStream<unknown>) {
    const reader = this.getReader();
    const iterator = {
      next: () => reader.read(),
      return: async () => {
        await reader.cancel().catch(() => {});
        reader.releaseLock();
        return { done: true as const, value: undefined };
      },
      [Symbol.asyncIterator]() {
        return iterator;
      },
    };
    return iterator;
  };
}