Subclasses can override #GstBinClass::add_element and #GstBinClass::remove_element
to update the list of children in the bin.
The #GstBinClass::handle_message method can be overridden to implement custom
message handling.
#GstBinClass::deep_element_added will be called when a new element has been
added to any bin inside this bin, so it will also be called if a new child
was added to a sub-bin of this bin. #GstBin implementations that override
this message should chain up to the parent class implementation so the
#GstBin::deep-element-added signal is emitted on all parents.
Subclasses can override #GstBinClass::add_element and #GstBinClass::remove_element to update the list of children in the bin.
The #GstBinClass::handle_message method can be overridden to implement custom message handling.
#GstBinClass::deep_element_added will be called when a new element has been added to any bin inside this bin, so it will also be called if a new child was added to a sub-bin of this bin. #GstBin implementations that override this message should chain up to the parent class implementation so the #GstBin::deep-element-added signal is emitted on all parents.