desp: Apply despiking to a given subset
In grahamstewart12/tidyflux:

This is a low level function not intended to be used on its own. It is utilized by despike that should be used instead.

1	desp(b1, b2 = b1, rb1, rb2 = rb1, z, c)

`z`	A numeric value. MAD scale factor.
`c`	A numeric value. `mad` scale factor. Default is `3 * mad constant` (`i.e. 3 * 1.4826 = 4.4478`).
`block_1`	The double-differenced `var` time series with appropriate block size.
`block_2`	Serves for computing despiking threshold and can be from the same block as `block_1` (default) or from the whole year (more conservative when less data available).
`ref_block_1`	`var` values from appropriate block for finding false-flagged spikes by comparison with scaled median absolute deviation.
`ref_block_2`	`var` values for computing median and mad from the same block as `ref_block_1` (default) or whole year (more conservative when less data available).