text: var once = require('once');
  
  var noop = function() {};
  
  var isRequest = function(stream) {
  	return stream.setHeader && typeof stream.abort === 'function';
  };
  
  var isChildProcess = function(stream) {
  	return stream.stdio && Array.isArray(stream.stdio) && stream.stdio.length === 3
  };
  
  var eos = function(stream, opts, callback) {
  	if (typeof opts === 'function') return eos(stream, null, opts);
  	if (!opts) opts = {};
  
  	callback = once(callback || noop);
  
  	var ws = stream._writableState;
  	var rs = stream._readableState;
  	var readable = opts.readable || (opts.readable !== false && stream.readable);
  	var writable = opts.writable || (opts.writable !== false && stream.writable);
  
  	var onlegacyfinish = function() {
  		if (!stream.writable) onfinish();
  	};
  
  	var onfinish = function() {
  		writable = false;
  		if (!readable) callback.call(stream);
  	};
  
  	var onend = function() {
  		readable = false;
  		if (!writable) callback.call(stream);
  	};
  
  	var onexit = function(exitCode) {
  		callback.call(stream, exitCode ? new Error('exited with error code: ' + exitCode) : null);
  	};
  
  	var onclose = function() {
  		if (readable && !(rs && rs.ended)) return callback.call(stream, new Error('premature close'));
  		if (writable && !(ws && ws.ended)) return callback.call(stream, new Error('premature close'));
  	};
  
  	var onrequest = function() {
  		stream.req.on('finish', onfinish);
  	};
  
  	if (isRequest(stream)) {
  		stream.on('complete', onfinish);
  		stream.on('abort', onclose);
  		if (stream.req) onrequest();
  		else stream.on('request', onrequest);
  	} else if (writable && !ws) { // legacy streams
  		stream.on('end', onlegacyfinish);
  		stream.on('close', onlegacyfinish);
  	}
  
  	if (isChildProcess(stream)) stream.on('exit', onexit);
  
  	stream.on('end', onend);
  	stream.on('finish', onfinish);
  	if (opts.error !== false) stream.on('error', callback);
  	stream.on('close', onclose);
  
  	return function() {
  		stream.removeListener('complete', onfinish);
  		stream.removeListener('abort', onclose);
  		stream.removeListener('request', onrequest);
  		if (stream.req) stream.req.removeListener('finish', onfinish);
  		stream.removeListener('end', onlegacyfinish);
  		stream.removeListener('close', onlegacyfinish);
  		stream.removeListener('finish', onfinish);
  		stream.removeListener('exit', onexit);
  		stream.removeListener('end', onend);
  		stream.removeListener('error', callback);
  		stream.removeListener('close', onclose);
  	};
  };
  
  module.exports = eos;
  