`with_base_url` sounds like it follows the withr/etc. pattern but doesn't

[brookslogan]

Some R packages have a pattern for with_* functions where they will try to run some code with some setup and mandatory cleanup, similar to the Python with statement. with_base_url sounds very much like withr::with_options, etc. It'd be nice to either follow this with-statement-like pattern or find another name for this function.

[dshemetov]

So this function is intended to work like this

covidcast("fb-survey", "smoothed_cli", "day", "nation", epirange(20210405, 20210410), "us") %>%
  with_base_url("https://staging.delphi.cmu.edu/epidata/") %>% 
  fetch_df()

I'm not used to withr, so this didn't throw me off. Is there an interface change we can make to make it more intuitive to withr users? Something like

with_base_url("https://staging.delphi.cmu.edu/epidata/", 
  covidcast("fb-survey", "smoothed_cli", "day", "nation", epirange(20210405, 20210410), "us")
) %>%
  fetch_df()

covidcast("fb-survey", "smoothed_cli", "day", "nation", epirange(20210405, 20210410), "us") %>%
  with_base_url("https://staging.delphi.cmu.edu/epidata/", .) %>%
  fetch_df()

and with_base_url will modify the global_base_url variable inherited from constants.R?