xdf_define_arrays() specifies the number of arrays and its strides for upcoming calls to xdf_write(3) and
xdf_read(3) using xdf. This function is used to configure the upcoming transfer. As such, it must be
called before xdf_prepare_transfer(3) (calling it after will produce an error). However the function may
be called several times but only the last call is meaningful for the transfer.
narrays specifies the number of arrays that will be provided in the argument list of xdf_write(3) or
xdf_read(3).
strides argument should point to an array of narrays unsigned int corresponding respectively to the
stride of each arrays that will be supplied to the upcoming call to xdf_write(3) or xdf_read(3). The
stride corresponds to the length in byte between two consecutive samples of the same channel in the
array.