Fills this buffer with <tt>NUL (0x00)</tt> starting at the current
{@code writerIndex} and increases the {@code writerIndex} by the
specified {@code length}.
If {@code this.writableBytes} is less than {@code length}, {@link #ensureWritable(int)}
will be called in an attempt to expand capacity to accommodate.
@param length the number of <tt>NUL</tt>s to write to the buffer
Fills this buffer with <tt>NUL (0x00)</tt> starting at the current {@code writerIndex} and increases the {@code writerIndex} by the specified {@code length}. If {@code this.writableBytes} is less than {@code length}, {@link #ensureWritable(int)} will be called in an attempt to expand capacity to accommodate.
@param length the number of <tt>NUL</tt>s to write to the buffer