fn decode(mut input io.Reader) ?i64
Decode a single VLQ value from the input stream, returning the value.
Supports all numbers that can be represented by a sign bit and a 63 bit
[-(2^63 - 1), 2^63 - 1].
i64::MIN = -(2^63) cannot be represented in that form, and this
NOT IMPLEMENTED: function will return
Error::Overflowed when attempting to decode it.
fn encode(value i64, mut output io.Writer) ?
Encode a value as Base64 VLQ, sending it to the writer