Isochronous Channel Throughput test on nRF52840

Hello,

I want to test the throughput of Isochronous Channel using ncs sample code "iso_connected_benchmark". So far I can successfully build the code and run in central mode on nRF52840 EVB to listen for incoming messages. 

However, if I select  peripheral mode, the console shows the errors below:

Peripheral role
Choose device role - type c (central role) or p (peripheral role), or q to quit: [00:00:03.172,576] <inf> iso_connected: Registering ISO server
[00:00:03.172,607] <err> iso_connected: ISO server register failed: -134
[00:00:03.172,637] <err> iso_connected: Could not disconnect ACL: -128
[00:00:03.172,637] <err> iso_connected: Could not clean up: -134
[00:00:03.172,637] <inf> iso_connected: Test complete: -134

The first error returns -134, which as I read from the codes it means the LE CIS peripheral is feature not supported.

How can I test the throughput using nRF52840?

Thanks,

Sheldon