Revert "Merge pull request #9193 from pipu/v3_flatbuffers"

This reverts commit fa22b126285674e3e0d0f2d5f2f39c56987b483e, reversing
changes made to 8dce62b94c3c7a9583352018f03da55b6def14d9.
Merge pull request #9222 from ricardoquesada/revert_flatbuffers

Revert "Merge pull request #9193 from pipu/v3_flatbuffers"