pylibrabbitmq noticeable difference in timing data.

pub.py

from datetime import datetime
import librarbbitmq

msg = 'x'*20000
M_PROP = {'delivery_mode': 1}
connection = librabbitmq.connecetion(...)
channel = connection.channel()
start = datetime.now()
for _ in xrange(count):
    connection._basic_publish(1, msg, X, RK, M_PROP, False, False)
end1 = datetime.now()
channel.close() 
end2 = datetime.now()
print end1-start, end2-start