Gio.OutputStream.prototype.splice

function splice(source: Gio.InputStream, flags: Gio.OutputStreamSpliceFlags, cancellable: Gio.Cancellable): Number(gssize) {
    // Gjs wrapper for g_output_stream_splice()
}

Splices an input stream into an output stream.

source

a Gio.InputStream.

flags

a set of Gio.OutputStreamSpliceFlags.

cancellable

optional Gio.Cancellable object, null to ignore.

Returns

a #gssize containing the size of the data spliced, or -1 if an error occurred. Note that if the number of bytes spliced is greater than %G_MAXSSIZE, then that will be returned, and there is no way to determine the actual number of bytes spliced.