ensureCapacity(minCapacity) {
			// overflow-conscious code
			if (minCapacity - this.buf.length > 0)
				this.grow(minCapacity);
		}
Increases the capacity if necessary to ensure that it can hold
at least the number of elements specified by the minimum
capacity argument.

@param minCapacity the desired minimum capacity
@throws OutOfMemoryError if {@code minCapacity < 0}.  This is
interpreted as a request for the unsatisfiably large capacity
{@code (long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE)}.