Inproc socket doesn't seem to be released immediately after a socket.Close()

gistfile1.go

package atest

import (
    "testing"

    zmq "github.com/pebbe/zmq4"
)

func TestA(t *testing.T) {
    socket, err := zmq.NewSocket(zmq.PUSH)
    if err != nil {
        panic(err)
    }
    if err = socket.Bind("inproc://input"); err != nil {
        panic(err)
    }
    if err = socket.Close(); err != nil {
        panic(err)
    }
}

func TestB(t *testing.T) {
    socket, err := zmq.NewSocket(zmq.PUSH)
    if err != nil {
        panic(err)
    }
    if err = socket.Bind("inproc://input"); err != nil {
        panic(err)
    }
    if err = socket.Close(); err != nil {
        panic(err)
    }
}