How specify jsonb type on RowCoder for jdbc connector

[Juan Romero <js...@gmail.com>]

Hello,

Currently Im trying to make inserts to a postgres table with this schema:

id: int,
message: jsonb,
source: str

the issue is that I cant find a way to specify the jsonb type on the
RowCoder, so I tried specifying dict and json on the NamedTuple but it
doesnt work. How should I create the RowCoder for accept that type of field?

Also I cant see how specify if some field can be nullable, how create a
RowCoder that accepts that the source field sometimes can be null?

Thanks for the help.