https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.1.0/com.ibm.zos.v2r1.ioea700/zfshang.htm
"When the hang detector determines that a task has remained in the same location for a predefined period of time, it attempts to determine why it is not making progress."
Is there a hang detector in openzfs on osx?