Need to get the 'fd' of EGL OutputStream of libargus producer

Hi,
This method is not tested and verified. May not work properly. There is a user working on a similar use-case. Please refer to
Cross eglstream copy CUeglFrame failed

From Jetpack 4.6, we have NvBuffer APIs for sharing buffers between process. It is also based on unix domain socket. We are working on a sample demonstrating this use-case. Will share it when it is ready.