I need a new function for send rate

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I show you in the example what I need:
Start()
{
PhotonNetwork.sendRate = 1;
}

public void UpdateItem()
{
   if(PhotonNetwork.nextSendinMilliseconds < 300)
   {
   PhotonNetwork.RaiseEvent(...);
   }
   else
   {
   PhotonNetwork.RaiseEvent(...)
   PhotonNetwork.SendOutgoingCommands();
   }
}
I want to send other players my new item for example. But instead of "wasting" a new message for that I just check whether the next message which is called regulary by sendrate will be send within the next 300ms. If so it will just add my message onto it; if not it will add the message to the queue and send it directly with SendOutgoingCommands();

Where can I find the time left from SendRate to usr it as shown? Is it even possible to set sendRate to 0 and handle it all by my self?

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