def broadcast(self, obj: TBroadcast, src: int = 0) -> TBroadcast:
        r"""Send a tensor from one process to all others.

        This method needs to be called on all processes. Failing to do so will cause your program to stall forever.

        Args:
            obj: The object to broadcast to all other members. Any serializable object is supported, but it is
                most efficient with the object being a :class:`~torch.Tensor`.
            src: The (global) rank of the process that should send the data to all others.

        Return:
            The transferred data, the same value on every rank.

        """
        self._validate_launched()
        return self._strategy.broadcast(obj, src=src)
Send a tensor from one process to all others.

        This method needs to be called on all processes. Failing to do so will cause your program to stall forever.

        Args:
            obj: The object to broadcast to all other members. Any serializable object is supported, but it is
                most efficient with the object being a :class:`~torch.Tensor`.
            src: The (global) rank of the process that should send the data to all others.

        Return:
            The transferred data, the same value on every rank.

        
src/lightning/fabric/fabric.py