private static InternalScriptContext getGrinderInstance() {
		InternalScriptContext grinder = Grinder.grinder;
		if (grinder == null || grinder.getThreadNumber() == -1) {
			throw new RuntimeException("This method should be called in the worker thread context.");
		}
		return grinder;
	}
Get this thread unique id among all threads in the all agents.

@return unique id b/w from 0 to total thread count.
@since 3.2.3
ngrinder-runtime/src/main/java/net/grinder/util/GrinderUtils.java