Hi guys!
For your happyness i write other article about ML.NET concept for you!
Today is the turn of Estimator.
Estimator
the Estimator is an object that learn by data. The result of training is a Transformer
Let’s see the IEstimator interface.

Yes as you thought you can create sequences of Estimator and you can thik about it as a single Estimator.
This property is the Append(). With this you can concatenate a lot of Estimator.
Sequence of Estimator
Lazy Data? So Lazy Transformer!But Data reader? Lazy too!! And Estimator? Eager!
References: