Convert datetime object to character string
ic_char_datetime(x, zulu = FALSE)
x <- ic_datetime("20180809T160000")
ic_char_datetime(x) == "20180809T160000"
#> [1] TRUE
x <- ic_datetime("20180809T160000Z")
ic_char_datetime(x, zulu = TRUE) == "20180809T160000Z"
#> [1] TRUE
ic_char_date(as.Date("1985-12-26"))
#> [1] "19851226"