could you provide a 4mc example for flink about 4mc HOT 1 OPEN

I don't have a Flink example ready to go but can give you some input.
We are going to use it soon in our data chain and when we have a decent example will also add in examples folder.

// 1) create hadoop config and set your hadoop host/stuff
Configuration hadoopConfig = new Configuration();
hadoopConfig.set("fs.defaultFS", "hdfs://yourHdfsHost:8020");
hadoopConfig.set("io.compression.codecs", "...."); // make sure to set codecs

// 2) get job conf and configure 4mc for your proto message
Job jobConf = Job.getInstance(hadoopConfig);
FourMcEbProtoInputFormat.setInputFormatClass(YOURMSG.YourProtoMessage.class, jobConf);

// 3) create input from hdfs
DataSet<Tuple2<LongWritable, ProtobufWritable>> input =
env.readHadoopFile(new FourMcEbProtoInputFormat(), LongWritable.class, ProtobufWritable.class, "hdfs://path_to_your_file.4mc", jobConf);

// 4) add more in union or selecting multiple files at once

// 5) use the data set

from 4mc.