https://github.com/ChALkeR/safer-buffer/blob/master/Porting-Buffer.md#variant-2 / nodejs/node#19079

Fixes #260.

…ting instance (#269)

… `filter`/`serializeDate` (#279)

… & no options are provided

…on-array source

…urce

…ith a non-string value

Note that all these tests passed already. Since the only time a
formatter is called is in a context where it is concatenated with
another string using `+`, this is a redundant step. However, for
pedantic correctness and documentation, the contract for formatters is
to always return a string.

This is an experiment; I intend to use 100% of funds to support the OSS community and my OSS projects' costs.

- `defaultEncoder`=> `defaultDecoder`