KNOW ALL PERSONS BY THESE PRESENTS that STONEBRIDGE
2017 OFFSHORE, L.P. (the "Company") does hereby make,
constitute and appoint each of Yvette Kosic,
Jamison Yardley, Jennifer Lee and Jess J. Morrison, acting
individually, its true and lawful attorney, to execute and
deliver in its name and on its behalf whether the Company
is acting individually or as representative of others, any
and all filings required to be made by the Company under
the Securities Exchange Act of 1934, (as amended, the
"Act"), with respect to securities which may be deemed to
be beneficially owned by the Company under the Act, giving
and granting unto each said attorney-in-fact power and authority
to act in the premises as fully and to all intents and purposes
as the Company might or could do if personally present by one
of its authorized signatories, hereby ratifying and confirming
all that said attorney-in-fact shall lawfully do or cause to
be done by virtue hereof.
THIS POWER OF ATTORNEY shall remain in full force and effect
until the earlier of (i) March 15, 2022 and (ii) such time
that it is revoked in writing by the undersigned; provided that
in the event the attorney-in-fact ceases to be an employee of
the Company or its affiliates or ceases to perform the function
in connection with which he/she was appointed attorney-in-fact
prior to such time, this Power of Attorney shall cease to have
effect in relation to such attorney-in-fact upon such
cessation but shall continue in full force and effect in
relation to any remaining attorneys-in-fact. The Company has the
unrestricted right unilaterally to revoke this Power of Attorney.
This Power of Attorney shall be governed by, and construed in
accordance with, the laws of the State of New York, without
regard to rules of conflicts of law.
IN WITNESS WHEREOF, the undersigned has duly subscribed these
presents as of March 15, 2019.
STONEBRIDGE 2017 OFFSHORE, L.P.
By: Bridge Street Opportunity Advisors, L.L.C.,
its General Partner
/s/ William Y. Eng
Name: William Y. Eng
Title: Attorney-in-Fact