function whether expected or not, rather than continue and try to compare invalid decoded results. Extend the unit test slightly to check the header. Remove go-test/deep dependency in favour of standard library reflect package.
Added support for FunctionCall message as per https://www.postgresql.org/docs/11/protocol-message-formats.html Adds unit test for Encode / Decode cycle and invalid message format errors. Fixes https://github.com/jackc/pgproto3/issues/23