public CommittableOffset(IInternalCommitter committer, GroupTopicPartitionOffset offset, string metadata)
 {
     Committer = committer;
     Offset    = offset;
     Metadata  = metadata;
 }
 /// <summary>
 /// CommittableSourceMessageBuilder
 /// </summary>
 public CommittableSourceMessageBuilder(IInternalCommitter committer, string groupId, Func <ConsumeResult <K, V>, string> metadataFromRecord)
 {
     Committer           = committer;
     GroupId             = groupId;
     _metadataFromRecord = metadataFromRecord;
 }