Inability to use a timestamp with milli/micro seconds

[antonioturdo]

In the comment of the formatTime method of the Client class it is argued that it is possible to use the result of microtime(true), which is a float. But in the only place where the method is used, in the message method of the same class, the value is cast to integer, making it effectively impossible to pass a timestamp with the precision of milli / micro seconds.

For reference, I saw that the cast was added in this refactoring.

I am going to open a PR to remove the cast to integer.