public static boolean isInRpcCallContext() {
    return CurCall.get() != null;
  }
Just return the current rpc call if it is a {@link ServerCall} and also has {@link CellScanner}
attached.
<p/>
Mainly used for reference counting as {@link CellScanner} may reference non heap memory.
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RpcServer.java