Why largest-thread-count value is always the same value as max-threads in EAP6 or EAP7

Issue

• The expectation is to see the peak of threads used in parallel, but the largest-thread-count is always the same as max-threads like shown in CLI below

[standalone@localhost:9999 /] /subsystem=ejb3/thread-pool=default:read-resource(include-runtime=true)
{
    "outcome" => "success",
    "result" => {
        "active-count" => 0,
        "completed-task-count" => 152L,
        "current-thread-count" => 10,
        "keepalive-time" => {
            "time" => 100L,
            "unit" => "MILLISECONDS"
        },
        "largest-thread-count" => 10,
        "max-threads" => 10,
        "name" => "default",
        "queue-size" => 0,
        "rejected-count" => 0,
        "task-count" => 153L,
        "thread-factory" => undefined
    }
}