vroom_fwf is not working correctly with n_max

[jimhester]

vroom::vroom_fwf(I("foo 1\nbar 2\nbaz 3\nqux 4"))
#> Rows: 4 Columns: 2
#> ── Column specification ────────────────────────────────────────────────────────
#> 
#> chr (1): X1
#> dbl (1): X2
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> # A tibble: 4 x 2
#>   X1       X2
#>   <chr> <dbl>
#> 1 foo       1
#> 2 bar       2
#> 3 baz       3
#> 4 qux       4

vroom::vroom_fwf(I("foo 1\nbar 2\nbaz 3\nqux 4"), n_max = 2)
#> Rows: 2 Columns: 2
#> ── Column specification ────────────────────────────────────────────────────────
#> 
#> chr (2): X1, X2
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> # A tibble: 2 x 2
#>   X1    X2               
#>   <chr> <chr>            
#> 1 foo   "1"              
#> 2 bar   "2\nbaz 3\nqux 4"

vroom::vroom_fwf(I("foo 1\nbar 2\nbaz 3\nqux 4"), n_max = 3)
#> Rows: 3 Columns: 2
#> ── Column specification ────────────────────────────────────────────────────────
#> 
#> chr (2): X1, X2
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> # A tibble: 3 x 2
#>   X1    X2        
#>   <chr> <chr>     
#> 1 foo   "1"       
#> 2 bar   "2"       
#> 3 baz   "3\nqux 4"

vroom::vroom_fwf(I("foo 1\nbar 2\nbaz 3\nqux 4"), n_max = 4)
#> Rows: 4 Columns: 2
#> ── Column specification ────────────────────────────────────────────────────────
#> 
#> chr (1): X1
#> dbl (1): X2
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> # A tibble: 4 x 2
#>   X1       X2
#>   <chr> <dbl>
#> 1 foo       1
#> 2 bar       2
#> 3 baz       3
#> 4 qux       4

^{Created on 2021-05-14 by the reprex package (v2.0.0)}