How to combine pushJSON() and setTimestamp() into single request about firebase-esp8266

[mobizt]

That operation returns HTTP code 500 Internal Server Error and payload
{
"error" : "Unexpected server error"
}

This means something error occurred in google side which they are not implemented the handle response or some unexpected error they didn't catch.

[mobizt]

Finally, I've found this is the bug due to ETag header was set by default in the library while server timestamp was included in JSON data. This causes the internal server error response.

Now it fixed, please update the library (git version).