Is there a app for this?
It it po
Within the Android emulator, you can now throttle the network speed directly.

Press the 3 dots button, followed by 'Cellular' on the left. You can then select the network type and signal strength.
Speeds for reference in increasing kbps:
UP DOWN
-------- ----------
gsm GSM/CSD 14.4 14.4
hscsd HSCSD 14.4 57.6
gprs GPRS 28.8 57.6
umts UMTS/3G 384.0 384.0
edge EDGE/EGPRS 473.6 473.6
hsdpa HSDPA 5760.0 13,980.0
lte LTE 58,000.0 173,000.0
evdo EVDO 75,000.0 280,000.0
full No limit ∞ ∞