Loading RSelenium does seem to be "longer than expected", but this may depend on your local specs. What's the timing look like? Does it take a a second longer than other packages or is it much longer?
Other option is to run microbenchmark on require(Rselenium) (see example below). Depending on the results, it might be worth making a separate post in order to diagnose the issue.
# pkgs
library(tidyverse)
library(microbenchmark)
# set seed
set.seed(321)
# performance testing: run require(RSelenium) 1000 times (results are in milliseconds)
rselenium.load.times <- microbenchmark::microbenchmark(
require(RSelenium),
times = 1000
)
#> Loading required package: RSelenium
# assign trials to new object
rselenium.trials <- data.frame(
num = seq(1:1000),
time = rselenium.load.times$time,
stringsAsFactors = F
)
# autoplot function
autoplot.microbenchmark(rselenium.load.times)
#> Coordinate system already present. Adding new coordinate system, which will replace the existing one.

# plot individual trials
ggplot(data = rselenium.trials, aes(x = num, y = time)) +
geom_point() +
theme_minimal()

Created on 2018-07-24 by the reprex
package (v0.2.0).