private void ensureCapacity(int amount) {
    if (overflowBuf != null) {
      return;
    }
    int remainingSpace = buffer.capacity() - buffer.position();
    if (amount > remainingSpace) {
      realFlush(false);
    }
  }
Create message streamers splitting into versioned streamers, if required, for given list of
connections to remote nodes. This method can either return a single MsgStreamer object or a
List of MsgStreamer objects.
geode-core/src/main/java/org/apache/geode/internal/tcp/MsgStreamer.java