Message sending currently fails with INVALID_JSON if messageId type is something other than string (number etc); string is explicitly required in the FCM XMPP spec.
The resulting nack does not contain a valid message_id as the server does not consider the original message to contain one, so the error is silently dropped by Sender rather than reported as a Result, and is difficult to discover. Enforcing a strict messageId type in the constructor at least ensures that invalid, non-null messageIds are reported as such, rather than silently ignored.
Suspect this may be the cause of #12, if numeric IDs are being used in those cases.
Message sending currently fails with INVALID_JSON if messageId type is something other than string (number etc); string is explicitly required in the FCM XMPP spec.
The resulting nack does not contain a valid message_id as the server does not consider the original message to contain one, so the error is silently dropped by Sender rather than reported as a Result, and is difficult to discover. Enforcing a strict messageId type in the constructor at least ensures that invalid, non-null messageIds are reported as such, rather than silently ignored.
Suspect this may be the cause of #12, if numeric IDs are being used in those cases.