fromZigzag

ubyte[] b1 = [0b0000_0001];
assert(fromVarint!int(b1) == 1);

ubyte[] b128 = [0b1000_0000, 0b0000_0001];
assert(fromVarint!int(b128) == 128);

ubyte[] b300 = [0b1010_1100, 0b0000_0010];
assert(fromVarint!int(b300) == 300);

ubyte[] bneg1 = [0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x01];
assert(-1 == fromVarint!int(bneg1));

ubyte[] bneg1_sint = [0x01];
assert(-1 == fromVarint!int(bneg1_sint).fromZigzag);

ubyte[] b1_sint = [0x02];
assert(1 == fromVarint!int(b1_sint).fromZigzag);