Encoding enumeration only has one value Encoding.Utf8 which is ToString()'d and sent to the server as "Utf8"; the server fails with HTTP 400 Bad Request because the expected value for Encoding is "UTF-8":

HTTP/1.1 400 Bad Request
Content-Length: 259
Content-Type: application/json; version=2.0.0-N1QL
Date: Thu, 20 Jun 2019 19:49:21 GMT

{
"requestID": "a9ecd94c-0271-41b3-8e0d-8d60888bebf4",
"errors": [

Unknown macro: {"code"}

],
"status": "fatal",
"metrics":

Unknown macro: {"elapsedTime"}

}