Is it possible to specify multi hosts dsn for connection pool?

Is it possible to connect to several hosts (one master and replicas) from ConnectionPool (interface like libpq provides)?

I mean the following: https://www.postgresql.org/docs/current/static/libpq-connect.html
```
# Read sessions
postgresql://host1:123,host2:456/somedb?target_session_attrs=any

# Read-write sessions
postgresql://host1:123,host2:456/somedb?target_session_attrs=read-write
```
I enumerate all postgresql hosts and in target_session_attrs parameter specify `read-write` if i need master.

Or i should create separate connection pools for master & replicas servers?

How that functionality (switching between hosts depending on target_session_attrs attrs, re-connecting on master switch) can be implemented in asyncpg?

Start by reviewing asyncpg's ConnectionPool interface and the linked PostgreSQL libpq documentation for multi-host DSNs and target_session_attrs. The issue names no source files or tests; done would be clear support for multi-host selection and reconnection, or a documented alternative using separate pools.

Written by the indexing model from the issue text.