Check value of X-RI header before sending next request

[judith-bourque]

Issue

#120

Proposed solution

"The returned HTTP header X-Rl contains the number of requests remaining in the current rate limit window. X-Ttl contains the seconds until the limit is reset.

Your implementation should always check the value of the X-Rl header, and if its is 0 you must not send any more requests for the duration of X-Ttl in seconds." (source)

Headers:

• X-Rl: Number of requests remaining in current rate limit window
• X-Ttl: seconds until limit is reset

Steps:

• Add sleep to get_location()

# Pseudocode
if (resp$X-RI == 0) {
    sys.sleep(resp$X-Ttl seconds)
}

# Relevant code
httr2::resp_header(resp, "X-Rl")
httr2::resp_header(resp, "X-Ttl")