Function grpcio_sys::grpc_channel_ping

pub unsafe extern "C" fn grpc_channel_ping(
    channel: *mut grpc_channel, 
    cq: *mut grpc_completion_queue, 
    tag: *mut c_void, 
    reserved: *mut c_void
)

Ping the channels peer (load balanced channels will select one sub-channel to ping); if the channel is not connected, posts a failed.