Bug Fix: Skip downloading invalid cURL range, such was in the RAP model wind messages.

[blaylockbk]

The RAP model uses GRIB submessages to store the wind vectors (UGRD and VGRD).

The byte ranges were incorrect for the first grib submessage, and would result in the entire file being downloaded instead of a single message.

To fix this, I simply check the byte range is valid (length of byte range is greater than 0). If the byte range is not valid, Herbie simply skips downloading that message.

from herbie import Herbie

model = "rap"
product = "awp130pgrb"
dtg = "2023-12-25 21:00"
fhr = 0
H = Herbie(dtg, model=model, product=product, fxx=fhr)
H.inventory(searchString="GUST|UGRD:10 m|VGRD:10 m|TMP:2 m|DPT:2 m")

ds = H.xarray(
    searchString="GUST|UGRD:10 m|VGRD:10 m|TMP:2 m|DPT:2 m",
    verbose=True,
    overwrite=True,
    remove_grib=False
)