RPC layer's wrapper on m0_net_buffer. rpc_buffer carries one packet at a time.
NOTE: rpc_buffer and packet are kept separate, even though their lifetime is same at this point. A buffer can carry only one packet at some point. There is a limit on number of packets that can be "in-flight". In near future we might want to keep per m0_rpc_chan buffer pool with few pre-allocated buffers. In that case same buffer will carry many packets during its lifetime (but only one at a time).
Definition at line 83 of file frmops.c.