config/src/main/java/org/springframework/security/config/annotation/authentication/configurers/provisioning/UserDetailsManagerConfigurer.java
@SuppressWarnings("unchecked")
	public final C withUser(User.UserBuilder userBuilder) {
		this.users.add(userBuilder.build());
		return (C) this;
	}
@SuppressWarnings("unchecked")
	public final C withUser(User.UserBuilder userBuilder) {
		this.users.add(userBuilder.build());
		return (C) this;
	}
Allows adding a user to the {@link UserDetailsManager} that is being created. This
method can be invoked multiple times to add multiple users.

@param userBuilder the user to add. Cannot be null.
@return the {@link UserDetailsBuilder} for further customizations