Exception when buffer a small-angle polygon

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I use this points as polygon soordinates:

X Y

0 0/ 50 100/ 30 130/ 124 290/ 82 144/ 129 289/ 120 140/ 170 135/ 0 0/

then:

geos::geom::Polygon* poly; poly->buffer( 25 ); throws util::TopologyException

finally, i find the reason: default quadrantSegments is 8,so i try "poly->buffer( 25, 6 )" instead，everything is OK;