#19 searching instument has a long time

[jik.zhao]

When I use the pyvisa connect a instrument by usbtmc protocol, it cost about six seconds.
The code like this:

import visa
mangers = visa.get_instuments_list()
resource = visa.get_instrument(mangers[0])

But when I only use get_instrument("USB::XXXXX::INSTR") or pyvisa43, it connect very soon.The pyvisa43 code like this:

import pyvisa43 as vpp43
manger = vpp43.open_default_resource_manger()
resource = vpp43.find_resource(manger, "USB?*INSTR")
device = vpp43.open(manger, resource[2])

I use the NI I/O Trace catch the trace, find the function viFindRsrc() takes a long
time. I try to find the reason, but I don't know why.