While reviewing the Pull Request for this issue:
I realized that we can improve the default TimestampType as follows:
1. We could make it parameterizable so that it can also take a custom
timezone (UTC) during mapping.
2. We could also define a default timezone so that we don't rely on the JVM
one. This might be desirable when the UI requires to display the time in a
certain timezone, while we want to save all timestamps in UTC.
Let me know what you think.