New a config with options.

WithDecoder with config decoder.

WithLogger with config logger.

WithResolver with config resolver.

WithSource with config source.

ErrNotFound is key not found.

ErrTypeAssert is type assert error.

KeyValue is config key value.

Config is a config interface.

Reader is config reader.

Source is config source.

Value is config value interface.

Watcher watches a source for changes.

Decoder is config decoder.

Observer is config observer.

Option is config option.

Resolver resolve placeholder in config.