Zero-fill MRS data in the time domain.
zf(x, factor = 2, offset = 0)
# S3 method for class 'list'
zf(x, factor = 2, offset = 0)
# S3 method for class 'mrs_data'
zf(x, factor = 2, offset = 0)
# S3 method for class 'basis_set'
zf(x, factor = 2, offset = 0)
zero-filled data.