proto map is not support?

[khadgarmage]

my proto file has the keyworld: map<string,Object>
generate the php file by proto file,that is ok.
but, protobuf::decode is not ok, the data as following:
class tests\Storys#3 (4) {
public $data =>
array(1) {
[0] =>
class tests\Storys\DataEntry#26 (5) {
public $key =>
NULL
public $value =>
NULL
protected $_descriptor =>
class DrSlump\Protobuf\Descriptor#27 (4) {
...
}
protected $_extensions =>
array(0) {
...
}
protected $_unknown =>
array(1) {
...
}
}
}
protected $_descriptor =>
class DrSlump\Protobuf\Descriptor#5 (4) {
protected $class =>
string(12) "tests\Storys"
protected $name =>
string(12) "tests.Storys"
protected $fields =>
array(1) {
[1] =>
class DrSlump\Protobuf\Field#6 (8) {
...
}
}
protected $names =>
array(1) {
'data' =>
int(1)
}
}
protected $_extensions =>
array(0) {
}
protected $_unknown =>
array(0) {
}
}