Jeremiah wakes up

Jeremiah 31:26 - At this I awoke and looked around. My sleep had been pleasant to me.

I wonder how long it took Jeremiah (or almost any Bible write, for that matter) to write his book. That is, on how many different occasions did he have a message to write, and how long were the periods in between writings? Sometimes clues are given as when a historic event or a king's reign is mentioned. But in this case, Jeremiah just says that he woke up from a pleasant sleep in which the Lord had been speaking to him. When did that revelation start? Was it just a few sentences earlier (verse 23)? Was it a whole chapter? The whole book to this point?