v1.18.0

Features

• add client_options to base class (#132) (6851bb8)
• add OpenTelemetry tracing to spanner calls (#107) (4069c37)

Bug Fixes

• resume iterator on EOS internal error (#122) (45a1538)

Documentation

• add install reference for cloud trace exporter (opentelemetry) (#127) (23fcd4c)
• add instructions for using a Cloud Spanner emulator (#136) (808837b)
• add samples from spanner/cloud-client (#117) (8910771), closes #804 #815 #818 #887 #914 #922 #928 #962 #992 #1004 #1035 #1055 #1063 #1093 #1107 #1121 #1158 #1138 #1186 #1192 #1207 #1254 #1316 #1354 #1376 #1377 #1402 #1406 #1425 #1441 #1464 #1519 #1548 #1633 #1742 #1836 #1846 #1872 #1980 #2068 #2153 #2224 #2198 #2251 #2295 #2356 #2392 #2439 #2535 #2005 #2721 #3093 #3101 #2806 #3377
• typo fix (#109) (63b4324)