(numeric) The adjustment of the progress update,
where adjust = 0 positions the message to the very left, and
adjust = 1 positions the message to the very right.
pad
(integer) Amount of padding on each side of the message,
where padding is done by spaces.
complete, incomplete
(function) Functions that take "complete" and
"incomplete" strings that comprise the progress bar as input and annotate
them to reflect their two different parts. The default is to annotation
them with two different background colors and the same foreground color
using the crayon package.
intrusiveness
(numeric) A non-negative scalar on how intrusive
(disruptive) the reporter to the user.
target
(character vector) Specifies where progression updates are
rendered.