Why was DataCollatorForNextSentencePrediction removed ?
# 🚀 Feature request

I want to ask a question about why DataCollatorForNextSentencePrediction was removed.
That class was implement in the pull request down below.
https://github.com/huggingface/transformers/pull/6572
It was so useful for me.
But, this feature is not included in the latest version.
Do anyone know why it was removed?

Or, is there any alternative features?

## Motivation

I need NSP feature to cunduct complete pre-training. 


This class is not necessary anymore: it was the same as `DataCollatorForLanguageModeling` while keeping the `nsp_labels` but  `DataCollatorForLanguageModeling` will keep any extra things (like `nsp_labels`) you pass to it. So you can just replace it with `DataCollatorForLanguageModeling`.<|||||>Thank you for your quick reply. 
Do you mean you just have to use TextDatasetForNextSentencePrediction before DataCollatorForLanguageModeling to conduct NSP?<|||||>Yes.<|||||>That makes sense.
Thank you very much for your help!