public Builder addExtensionHandlerFactory(ExtensionHandlerFactory extensionHandlerFactory) {
            this.extensionHandlerFactories.add(extensionHandlerFactory);
            return this;
        }
Adds an {@link ExtensionHandlerFactory} that will be used to find extension handlers when the {@link Builder#build()}} method is called.
@param extensionHandlerFactory An {@link ExtensionHandlerFactory} instance
@return The builder instance
core/src/main/java/org/jdbi/v3/core/extension/ExtensionMetadata.java