< An indentifier for the group of ports that share their availability status with
* each other. This is meant especially for handling cases where one 3.5 mm connector
* is used for headphones, headsets and microphones, and the hardware can only tell
* that something was plugged in but not what exactly. In this situation the ports for
* all those devices share their availability status, and PulseAudio can't tell which
* one is actually plugged in, and some application may ask the user what was plugged
* in. Such applications should get a list of all card ports and compare their
* availability_group fields. Ports that have the same group are those that need
* input from the user to determine which device was plugged in. The application should
* then activate the user-chosen port.
*
* May be NULL, in which case the port is not part of any availability group (which is
* the same as having a group with only one member).
*
* The group identifier must be treated as an opaque identifier. The string may look
* like an ALSA control name, but applications must not assume any such relationship.
* The group naming scheme can change without a warning.
*
* Since one group can include both input and output ports, the grouping should be done
* using pa_card_port_info instead of pa_source_port_info, but this field is duplicated
* also in pa_source_port_info (and pa_sink_port_info) in case someone finds that
* convenient.
*
* \since 14.0
< An indentifier for the group of ports that share their availability status with * each other. This is meant especially for handling cases where one 3.5 mm connector * is used for headphones, headsets and microphones, and the hardware can only tell * that something was plugged in but not what exactly. In this situation the ports for * all those devices share their availability status, and PulseAudio can't tell which * one is actually plugged in, and some application may ask the user what was plugged * in. Such applications should get a list of all card ports and compare their * availability_group fields. Ports that have the same group are those that need * input from the user to determine which device was plugged in. The application should * then activate the user-chosen port. * * May be NULL, in which case the port is not part of any availability group (which is * the same as having a group with only one member). * * The group identifier must be treated as an opaque identifier. The string may look * like an ALSA control name, but applications must not assume any such relationship. * The group naming scheme can change without a warning. * * Since one group can include both input and output ports, the grouping should be done * using pa_card_port_info instead of pa_source_port_info, but this field is duplicated * also in pa_source_port_info (and pa_sink_port_info) in case someone finds that * convenient. * * \since 14.0