jdbc targetServerType=slave with readonly connection

Hello,

the slave replication server does not seem to be recognized correctly when
using read-only jdbc connection and targetServerType=preferSlave.

Sample conn str
<entry
key="jdbc.url.readonly">jdbc:postgresql://master,slave/up?user=***&password=***&sslmode=require&ApplicationName=***&targetServerType=preferSlave&loadBalanceHosts=true&readOnly=true</entry>

From the docs I understands that since writes are not allowed in RO
transactions, the jdbc driver thinks it is connected to a slave. I think
the master/slave check should be corrected, or configurable.

Docs:
The master/slave distinction is currently done by observing if the server
allows writes

Thank you
Vladimir