add error handling example

readme.md

@@ -67,6 +67,30 @@ By default `concat-stream` will give you back the same data type as the type of
 
 If you don't specify an encoding, and the types can't be inferred (e.g. you write things that aren't int he list above), it will try to convert concat them into a `Buffer`.
 
+# error handling
+
+`concat-stream` does not handle errors for you, so you must handle errors on whatever streams you pipe into `concat-stream`. This is a general rule when programming with node.js streams: always handle errors on each and every stream. Since `concat-stream` is not itself a stream it does not emit errors. Here is a common example of handling errors in a stream:
+
+```
+var fs = require('fs')
+var concat = require('concat-stream')
+
+var readStream = fs.createReadStream('cat.png')
+var concatStream = concat(gotPicture)
+
+readStream.on('error', handleError)
+
+function gotPicture(imageBuffer) {
+  // process image
+}
+
+function handleError(err) {
+  // handle your error appropriately here
+  console.error(err) // print the error to STDERR
+  process.exit(1) // exit program with non-zero exit code
+}
+```
+
 # license
 
 MIT LICENSE