Allow highWaterMark for Channel to be configured

[arei]

It appears as if the highWaterMark setting for the channel write stream cannot be configured. freshChannel() does take an options object that it gets highWaterMark from, but new Channel(), createChannel() and createChannelConfirm() do not take options nor pass options through to freshChannel().

Setting highWaterMark may be desirable in some high volume systems.

[AsidStorm]

Sadly no upvotes or changes in 5 years (

May be it helps someone, we use this code to increase high water mark:

const TestChannel = await connection.createChannel();
TestChannel.__proto__.allocate = function() {
 this.ch = this.connection.freshChannel(this, {highWaterMark: 50000});
 return this;
};
await TestChannel.close();

const channel = await connection.createChannel();

[cressie176]

Can anyone confirm my understanding of what setting the high watermark it actually does please? From the node docs

The highWaterMark option is a threshold, not a limit: it dictates the amount of data that a stream buffers before it stops asking for more data. It does not enforce a strict memory limitation in general. Specific stream implementations may choose to enforce stricter limits but doing so is optional.

I understand this to mean that setting the high watermark will not block writes. However, it is possible the application code using amqplib implements such a mechanism when channel.publish returns false to indicate the buffer is saturated. Is this correct?

[cressie176]

I've created a PR