The ornamental design for an usbflashdrive, as shown and described.
FIG. 1 is a perspective view of an USB flash drive showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view thereof, a cap is separated from the USB flash drive.
The broken line showings of the joining portion of a housing in FIG. 4, the inside of a connector in FIG. 7 and the connector and a strap in FIG. 8 are included for the purpose of illustrating portions of the USB flash drive and environmental structure and form no part of the claimed design.