To address the slow initial query performance, it would be nice to have a warmup public method in CosmosContainer class before running the main query processors

[sjyang18]

Describe the bug
First query always shows very slow performance compared to subsequent queries.

To Reproduce
Set up Cosmos DB (sql core) with a container.
Populate 400 radom document data into the container.
Create a command line app with a query to pull top 300 records . Have multiple iteration with for loop to run this command inside the app.
Observe the first query is very slow to compare to subsequent query.

Expected behavior
There should be no noticeable performance between the first and subsequent same queries.

Actual behavior
Once the first query run with a long wait, the subsequent query does not show this slow performance.

Environment summary
SDK Version: V4 preview.1
Java JDK version: "1.8.0_222"
OS Version (e.g. Windows, Linux, MacOSX): Linux Ubuntu 18.04

Additional context
Add any other context about the problem here.