CURLOPT_BUFFERSIZE(3) on macOS

The text 8cdc02a38639, as macOS 10.12.5, macOS 10.12.4, macOS 10.12.3, macOS 10.12.2, macOS 10.12.1, macOS 10.12 shipped it.

set preferred receive buffer size

CURLOPT_BUFFERSIZE(3) on macOS now