def METHOD_NAME(vm, server_port_path, blob_path, blob_hash):
    """Test guest-initiated connections.
    This will start an echo server on the host (in its own thread), then
    start `TEST_CONNECTION_COUNT` workers inside the guest VM, all
    communicating with the echo server.
    """
    echo_server = Popen(
        ["socat", f"UNIX-LISTEN:{server_port_path},fork,backlog=5", "exec:'/bin/cat'"]
    )
    # Link the listening Unix socket into the VM's jail, so that
    # Firecracker can connect to it.
    attempt = 0
    # But 1st, give socat a bit of time to create the socket
    while not Path(server_port_path).exists() and attempt < 3:
        time.sleep(0.2)
        attempt += 1
    vm.create_jailed_resource(server_port_path)
    # Increase maximum process count for the ssh service.
    # Avoids: "bash: fork: retry: Resource temporarily unavailable"
    # Needed to execute the bash script that tests for concurrent
    # vsock guest initiated connections.
    pids_max_file = "/sys/fs/cgroup/system.slice/ssh.service/pids.max"
    ecode, _, _ = vm.ssh.run(f"echo 1024 > {pids_max_file}")
    assert ecode == 0, "Unable to set max process count for guest ssh service."
    # Build the guest worker sub-command.
    # `vsock_helper` will read the blob file from STDIN and send the echo
    # server response to STDOUT. This response is then hashed, and the
    # hash is compared against `blob_hash` (computed on the host). This
    # comparison sets the exit status of the worker command.
    worker_cmd = "hash=$("
    worker_cmd += "cat {}".format(blob_path)
    worker_cmd += " | /tmp/vsock_helper echo 2 {}".format(ECHO_SERVER_PORT)
    worker_cmd += " | md5sum | cut -f1 -d\\ "
    worker_cmd += ")"
    worker_cmd += ' && [[ "$hash" = "{}" ]]'.format(blob_hash)
    # Run `TEST_CONNECTION_COUNT` concurrent workers, using the above
    # worker sub-command.
    # If any worker fails, this command will fail. If all worker sub-commands
    # succeed, this will also succeed.
    cmd = 'workers="";'
    cmd += "for i in $(seq 1 {}); do".format(TEST_CONNECTION_COUNT)
    cmd += "  ({})& ".format(worker_cmd)
    cmd += '  workers="$workers $!";'
    cmd += "done;"
    cmd += "for w in $workers; do wait $w || exit -1; done"
    ecode, _, stderr = vm.ssh.run(cmd)
    echo_server.terminate()
    rc = echo_server.wait()
    # socat exits with 128 + 15 (SIGTERM)
    assert rc == 143
    assert ecode == 0, stderr