hasPrevMsgs property
Loadmore in end and loadmore in header hasPrevMsgs is used to tell widget there are more messages need load when scroll to first item offsetToTriggerLoadPrev is used to tell widget when scroll offset is reach to first item by loadPrevMessageOffset, onLoadPrevMsgs function will invoke, null or 0 will not enable automatically invoke load function
Implementation
final bool hasPrevMsgs;