* ftr: work pool

* rename WorkerPool -> FixedWorkerPool

* go fmt

* fix typo

* benchmark for ConnectionPool

* go fmt

* benchmark for ConnectionPool

* chan buffer extension for ConnectionPool benchmark

* reset benchmark tests for TaskPool

* reduce buffer of ConnectionPool

* unbounded chan benchmark

* reduce goroutine num

* ConnectionPool adopts task queue array

* apache license

* fix shadow variable

* remove done channel, add numWorkers

* go fmt

* fix wrong logger

* add newBaseWorkerPool

* remove ConnectionPoolConfig

* update comments

* update comments

* fix unittests

* Update base_worker_pool.go

* Update base_worker_pool.go

* fix newBaseWorkerPool bugs

* go fmt

* fix CountTaskSync bugs

* fix CountTask bug

* optimize code

* go fmt

* add SubmitSync test

* go fmt
Co-authored-by: Xin.Zh <dragoncharlie@foxmail.com>