code: public FastqBuilder withSequence(final String sequence)
  	{
  		if (sequence == null)
  		{
  			throw new IllegalArgumentException("sequence must not be null");
  		}
  		if (this.sequence == null)
  		{
  			this.sequence = new StringBuilder(sequence.length());
  		}
  		this.sequence.replace(0, this.sequence.length(), sequence);
  		return this;
  	}
docs: Return this FASTQ formatted sequence builder configured with the specified sequence.
  
  @param sequence sequence for this FASTQ formatted sequence builder, must not be null
  @return this FASTQ formatted sequence builder configured with the specified sequence