Classes implementing this interface know how to supply Messages.

This is a functional interface intended to support lambda expressions in log4j 2.

Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.

DEPRECATED: this class should not normally be used outside a Java 8+ lambda syntax. Instead, Supplier<Message> should be used as an anonymous class. Both this and Supplier will be removed in 3.0.