Step 1.
sync,
send http request at same time,
fast
async,
send http request wait after last request response back, one by one,
slow
https://transparentgov.net/json2tree/esri/server/folder2.html?org=services.arcgis.com&url=https%3A%2F%2Fservices.arcgis.com%2FP3ePLMYs2RVChkJx%2FArcGIS%2Frest%2Fservices&arcgis_online_token=&timeout=9000&select_folder=1204&select_layer=0&select_folder_text=USA_Major_Cities_+%3Csup%3EFeatureServer%3C%2Fsup%3E&select_layer_text=0+%26%23x21E2%3B+USA+Major+Cities+%3Csup%3EFeature+Layer%3Csub%3E+esriGeometryPoint%3C%2Fsub%3E%3C%2Fsup%3E
Step 2.
sync is fast, the concern is higher risk of loss data.
because by send 100, 1000 http request at same time to arcgis server,
depending on target server capacity,
when reach server CPU, RAM resource limit,
server may deny your http request cause data loss,
sync is fast, but higher risk of loss data.
Step 3.
9082, 8082, multi-try will try multiple times when server deny due to resource used up.
Step 4.
async is slow, because send http request in order,
1st request send,
wait until response back,
then 2nd request send
wait until done
then 3rd request ...
it is slow, but reliable,
you send request separate by long period,
arcgis server is less likely deny, less likely loss data.
Step 5.
limit 1k, 10k is for large data,
to avaid browser been freezed, limit max load data to 10k, or 1k,
Step 6.
fast100, for faster show up, only show top 100 row at beginning.
when you scroll,
it will show all rows
Step 7.
Step 8.
Step 9.