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It also proposes adding the ability to use the choose using target cluster's default for target topic configurations, rather than using the or source cluster's default for target topic configurations. For instance, users would be able to configure ConfigPropertyFilter to check if the configuration on the source topic is the default and decide whether or not to replicate it to the target topic. 

Proposed Changes

1) Extend ConfigPropertyFilter  class to have a new method called shouldReplicateSourceDefault which would always return true false by default. User would be able to configure this method to return false for a configuration that is DEFAULT_CONFIG.true in order to replicate source cluster's configurations with default values. 

2) Add a new configuration setting to MirrorMaker:

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