property_lock

Acquires a property lock, which is used to ensure thread safety when properties are changing.

Release the lock with property_unlock.

Note: Make sure the CamelFolderSummary lock is held before this lock, if there will be called any 'set' function on the this, to avoid deadlock when the summary would be set as dirty while another thread might try to read values from the this, waiting for the property lock and holding the summary lock at the same time.

Parameters: