code: public static FileBuffer allocate(File file, long initialCapacity) {
      return allocate(file, FileBytes.DEFAULT_MODE, initialCapacity, Long.MAX_VALUE);
    }
docs: Allocates a file buffer with the given initial capacity.
  <p>
  If the underlying file is empty, the file count will expand dynamically as bytes are written to the file.
  The underlying {@link FileBytes} will be initialized to the nearest power of {@code 2}.
  
  @param file The file to allocate.
  @param initialCapacity The initial capacity of the bytes to allocate.
  @return The allocated buffer.
  
  @see FileBuffer#allocate(java.io.File)
  @see FileBuffer#allocate(java.io.File, long, long)
  @see FileBuffer#allocate(java.io.File, String, long, long)