method FileHandle.appendFile
Usage
import { type FileHandle } from "node:fs/promises";
Alias of filehandle.writeFile().
When operating on file handles, the mode cannot be changed from what it was set
to with fsPromises.open(). Therefore, this is equivalent to filehandle.writeFile().
optional
options: (ObjectEncodingOptions & FlagAndOpenMode & { flush?: boolean | undefined; }) | BufferEncoding | null