Fastener

FIG. 1 is a top-side perspective view of a fastener; FIG. 2 is a bottom-side perspective view thereof; FIG. 3 is a front side elevation view thereof; FIG. 4 is a rear side elevation view thereof; FIG. 5 is a right side elevation view thereof; FIG. 6 is a left side elevation view thereof; FIG. 7 is a top plan view thereof; and, FIG. 8 is a bottom plan view thereof. The dashed broken lines in the drawings illustrate portions of the fastener that form no part of the claimed design. The dot-dash broken lines in the drawings illustrate the boundaries of the claimed design and form no part of the claimed design.