Submits PING frame. You don't have to send PING back when you received PING frame. The library automatically submits PING frame in this case.
If the |opaque_data| is non null, then it should point to the 8 bytes array of memory to specify opaque data to send with PING frame. If the |opaque_data| is null, zero-cleared 8 bytes will be sent as opaque data.
See Implementation
Submits PING frame. You don't have to send PING back when you received PING frame. The library automatically submits PING frame in this case.