code: def signedVarintSize(value):
    
    if value < 0: return 10
    if value <= 0x7f: return 1
    if value <= 0x3fff: return 2
    if value <= 0x1fffff: return 3
    if value <= 0xfffffff: return 4
    if value <= 0x7ffffffff: return 5
    if value <= 0x3ffffffffff: return 6
    if value <= 0x1ffffffffffff: return 7
    if value <= 0xffffffffffffff: return 8
    if value <= 0x7fffffffffffffff: return 9
    return 10
docs: Compute the size of a signed varint value.