Putting the Arena in the ArenaPool resets it

[kostaspap]

The way the Arena is meant to be used as highlighted here

 1) Construct Values via the Arena and Value.Set* calls.
 2) Marshal the constructed Values with Value.MarshalTo call.
 3) Reset all the constructed Values at once by Arena.Reset call.
 4) Go to 1 and re-use the Arena.

When using the ArenaPool, someone would have then to manually reset the Arena before returning it to the Pool

var pool fastjson.ArenaPool
....

func foo() {
....
  arena := pool.Get()
  defer func() {
    arena.Reset()
    pool.Put(arena)
  }
...
}

Which results in many repetitive code or worse, using the API wrong (e.g. putting the Arena in the ArenaPool before resetting it)

Looking at the description of the ArenaPool#Put method as described here
it makes me think that the intention was that ArenaPool#Put would reset the pool