docs: add size guidance to managedwriter
@@ -407,6 +407,9 @@ func (ms *ManagedStream) Close() error {
//
// Use the WithOffset() AppendOption to set an explicit offset for this append. Setting an offset for
// a default stream is unsupported.
+//
+// The size of a single request must be less than 10 MB in size.
+// Requests larger than this return an error, typically `INVALID_ARGUMENT`.
func (ms *ManagedStream) AppendRows(ctx context.Context, data [][]byte, opts ...AppendOption) (*AppendResult, error) {
pw := newPendingWrite(data)
// apply AppendOption opts
