Cross Reference: /external/nanopb-c/tests/callbacks

`Name`	`Date`	`Size`
Up to higher level directory
`callbacks.proto`	22-Oct-2020	`445`
`decode_callbacks.c`	22-Oct-2020	`3K`
`encode_callbacks.c`	22-Oct-2020	`2.5K`
`SConscript`	22-Oct-2020	`525`