Found few performance bottlenecks on benchmarking PostgreSQL CDC events. This Issue will focus on improving the ObjectMapper initialization (others will be filed as separate Issues).

`io.debezium.connector.postgresql.SourceInfo.sequence()` has a major performance bottleneck due to Initialization of `ObjectMapper` on every call (i.e., for every cdc row event). Pull Request will be raised with optimizing the `new ObjectMapper()` to `private static final` field.

JVisualVM Sampler metrics attached for 1M row CDC events on a table with 4 columns (NOOP DebeziumEngine.notifying)

Overall Performance improvement can range from approx `5% - 15%` depending upon row width (no of columns)

JMH Benchmarks

Benchmark                                        Mode  Cnt        Score        Error  Units
PostgresConnectorConfigPerf.benchmark_1_before  thrpt    3   550040.596 ±  16847.245  ops/s
PostgresConnectorConfigPerf.benchmark_2_after   thrpt    3  4347346.228 ± 108381.634  ops/s