Multiprocessing Logging Deadlock

gistfile1.txt

# See eg https://codewithoutrules.com/2018/09/04/python-multiprocessing/
# this deadlocks (Process p never terminates)
import logging
import multiprocessing
import threading
import time

class SlowHandler(logging.Handler):
    """ Waits 1 second, then prints """
    def emit(self, record):
        time.sleep(1)
        print(record)

# test
log = logging.getLogger(__name__)
log.addHandler(SlowHandler())

# Thread function
def thread_a():
    log.warn("Hi there")
   
# Process function
def proc_a():
    print("Starting process")
    log.warn("What's up?")
    print("Process complete!")
    
# Start thread    
t = threading.Thread(target=thread_a)
t.start()
# Wait half a second. Thread should be in the middle of calling the SlowHandler
time.sleep(0.5)
# Start process while in SlowHandler
p = multiprocessing.Process(target=proc_a)
p.start()
# Wait for thread to finish
t.join()
# wait for Process to finish. **Hangs**
print("waiting for Process to finish...")
p.join()