This would otherwise keep a lot of unused memory lying around,
and in particular add up to a page per chunk of memory overhead
for network reads, potentially opening a DoS vector if the resulting
`Buffer` objects are kept around indefinitely (e.g. stored in a list
and not concatenated until the socket finishes).
This fixes CVE-2018-7164.
Refs: https://github.com/nodejs-private/security/issues/186
Refs: 7c4b09b24b
PR-URL: https://github.com/nodejs-private/node-private/pull/128
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>