GalagoKeyValue
Key/value pair.
#GalagoKeyValue is a key/value pair, returned in some lists. It uses a string
for a key and a #GValue for the value type. As such, it can hold any value
that has a #GType.
@key:
@value:
@Returns:
@key_value:
@key_value:
@key:
@key_value:
@Returns:
@key_value:
@value:
@key_value:
@Returns: