[Ethernet Driver Porting API]
void vNetworkBufferRelease( xNetworkBufferDescriptor_t * const pxNetworkBuffer );
If the network buffer descriptor references an Ethernet buffer then the Ethernet buffer is also returned.
pxNetworkBufferGet() must not be called from an interrupt service routine (ISR).
A pointer to the network buffer descriptor being released
(returned to the IP stack).
Examples are provided on the Porting FreeRTOS to a Different Microcontroller page.