A friendlier version of InputStream's eachByte method that provides you a correctly-sized byte[] for the last invokation of the provided closure.

inputStreamEachChunkMethod.groovy

InputStream.metaClass.eachChunk << { int preferredChunkSize, Closure closure ->
    delegate.eachByte(preferredChunkSize) { buffer, bytesRead ->
        if (bytesRead == preferredChunkSize) {
            closure(buffer)
        } else if (bytesRead > 0) {
            byte[] data = new byte[bytesRead]
            System.arraycopy(buffer, 0, data, 0, bytesRead)
            closure(data)
        }
    }
}