Function ktxTexture2_CreateFromStdioStream 

pub unsafe extern "C" fn ktxTexture2_CreateFromStdioStream(
    stdioStream: *mut FILE,
    createFlags: ktxTextureCreateFlags,
    newTex: *mut *mut ktxTexture2,
) -> ktx_error_code_e

These four create a ktxTexture2 provided the data is in KTX2 format.