[ML-DataFrame] add sync api#41800

Merged

hendrikmuhs merged 5 commits intoelastic:feature-ml-data-frame-analyticsfrom

hendrikmuhs:feature-ml-data-frame-analytics-sync-api

May 6, 2019

Commits on May 3, 2019

introduce sync API for continuous data frames
Hendrik Muhs
committed
remove merge file
Hendrik Muhs
committed
register XContent in tests
Hendrik Muhs
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adapt hlrc test
Hendrik Muhs
committed
add named writables to abstractserializingtestcase
Hendrik Muhs
committed