Non-public API usage _LZ4_* with Unity 5.3.1p1

After successfully compiling and uploading my iOS app archive to iTunesConnect, I get this email:

Non-public API usage:

• The app references non-public symbols in choices: _LZ4_compressBound, _LZ4_compress_limitedOutput, _LZ4_decompress_safe

If method names in your source code match the private Apple APIs listed above, altering your method names will help prevent this app from being flagged in future submissions. In addition, note that one or more of the above APIs...

Non-public API usage _LZ4_* with Unity 5.3.1p1