snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

examples/data-channels-flow-control/README.md

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+# data-channels-flow-control
+This example demonstrates how to use the following property / methods.
+
+* func (d *DataChannel) BufferedAmount() uint64
+* func (d *DataChannel) SetBufferedAmountLowThreshold(th uint64)
+* func (d *DataChannel) BufferedAmountLowThreshold() uint64
+* func (d *DataChannel) OnBufferedAmountLow(f func())
+
+These methods are equivalent to that of JavaScript WebRTC API.
+See https://developer.mozilla.org/en-US/docs/Web/API/RTCDataChannel for more details.
+
+## When do we need it?
+Send or SendText methods are called on DataChannel to send data to the connected peer.
+The methods return immediately, but it does not mean the data was actually sent onto
+the wire. Instead, it is queued in a buffer until it actually gets sent out to the wire.
+
+When you have a large amount of data to send, it is an application's responsibility to
+control the buffered amount in order not to indefinitely grow the buffer size to eventually
+exhaust the memory.
+
+The rate you wish to send data might be much higher than the rate the data channel can
+actually send to the peer over the Internet. The above properties/methods help your
+application to pace the amount of data to be pushed into the data channel.
+
+
+## How to run the example code
+
+The demo code (main.go) implements two endpoints (offerPC and answerPC) in it.
+
+```
+                        signaling messages
+           +----------------------------------------+
+           |                                        |
+           v                                        v
+   +---------------+                        +---------------+
+   |               |          data          |               |
+   |    offerPC    |----------------------->|    answerPC   |
+   |:PeerConnection|                        |:PeerConnection|
+   +---------------+                        +---------------+
+```
+
+First offerPC and answerPC will exchange signaling message to establish a peer-to-peer
+connection, and data channel (label: "data").
+
+Once the data channel is successfully opened, offerPC will start sending a series of
+1024-byte packets to answerPC as fast as it can, until you kill the process by Ctrl-c.
+
+
+Here's how to run the code.
+
+At the root of the example, `pion/webrtc/examples/data-channels-flow-control/`:
+```
+$ go run main.go
+2019/08/31 14:56:41 OnOpen: data-824635025728. Start sending a series of 1024-byte packets as fast as it can
+2019/08/31 14:56:41 OnOpen: data-824637171120. Start receiving data
+2019/08/31 14:56:42 Throughput: 179.118 Mbps
+2019/08/31 14:56:43 Throughput: 203.545 Mbps
+2019/08/31 14:56:44 Throughput: 211.516 Mbps
+2019/08/31 14:56:45 Throughput: 216.292 Mbps
+2019/08/31 14:56:46 Throughput: 217.961 Mbps
+2019/08/31 14:56:47 Throughput: 218.342 Mbps
+ :
+```