function Channel(limit = 0) {
	this.limit = limit;
	this.buffer = [];
	this.readers = [];
	this.wakeRead = null;
	this.wakeWrite = null;
	this.readPromise = null;
	this.writePromise = null;
}
Channel.prototype.waitForRead = function() {
	if (this.readPromise === null) {
		this.readPromise = new Promise(resolve => {
			this.wakeRead = resolve;
		});
	}
	return this.readPromise;
};
Channel.prototype.waitForWrite = function() {
	if (this.writePromise === null) {
		this.writePromise = new Promise(resolve => {
			this.wakeWrite = resolve;
		});
	}
	return this.writePromise;
};
Channel.prototype.read = async function(wait = true) {
	if (this.wakeWrite !== null) {
		this.wakeWrite();
		this.wakeWrite = null;
	}
	if (this.buffer.length === 0) {
		if (wait) await this.waitForWrite();
		else return null;
	}
	return this.buffer.unshift();
};
Channel.prototype.write = async function(data, wait = true) {
	if (this.wakeRead !== null) {
		this.wakeRead();
		this.wakeRead = null;
	}
	if (wait && this.readers.length === 0) await this.waitForWrite();
	this.buffer.push(data);
};