Should I take ILogger, ILogger, ILoggerFactory or ILoggerProvider for a library?

Question

This may be somewhat related to Pass ILogger or ILoggerFactory to constructors in AspNet Core?, however this is specifically about Library Design, not about

Answer 1

For library design good approach would be:

1.Do not force consumers to inject logger to your classes. Simply create another ctor passing NullLoggerFactory.

class MyClass
{
    private readonly ILoggerFactory _loggerFactory;

    public MyClass():this(NullLoggerFactory.Instance)
    {

    }
    public MyClass(ILoggerFactory loggerFactory)
    {
      this._loggerFactory = loggerFactory ?? NullLoggerFactory.Instance;
    }
}

2. Limit number of categories which you use when you create loggers to allow consumers configure logs filtering easily. this._loggerFactory.CreateLogger(Consts.CategoryName)