Addreserve parameter to all USearchIndex constructors

This addresses#441

Summary

This PR adds an optionalreserve parameter to all three USearchIndex constructors to allow pre-allocation of memory for incoming vectors, improving performance when the expected number of vectors is known in advance.

Changes Made

1. First Constructor (Parameter-based)

• Before:

  publicUSearchIndex(MetricKind metricKind,ScalarKind quantization,ulong dimensions,ulong connectivity=0,ulong expansionAdd=0,ulong expansionSearch=0,bool multi= false)

• After:

  publicUSearchIndex(MetricKind metricKind,ScalarKind quantization,ulong dimensions,ulong connectivity=0,ulong expansionAdd=0,ulong expansionSearch=0,bool multi= false,ulong reserve=0)

2. Second Constructor (IndexOptions-based)

• Before:

  publicUSearchIndex(IndexOptions options)

• After:

  publicUSearchIndex(IndexOptions options,ulong reserve=0)

• Added reserve logic:if (reserve > 0) { this.IncreaseCapacity(reserve); }
• Added XML documentation for the new parameter

3. Third Constructor (File-based)

• Before:

  publicUSearchIndex(string path,bool view= false)

• After:

  publicUSearchIndex(string path,bool view= false,ulong reserve=0)

• Added reserve logic:if (reserve > 0) { this.IncreaseCapacity(reserve); }
• Added XML documentation for the new parameter

Benefits

• Performance: Pre-allocates memory to avoid reallocations during vector insertion
• Consistency: All constructors now support the same reserve functionality
• Backward Compatibility: Default value of0 ensures existing code continues to work

Usage Examples

// Pre-allocate for 1000 vectorsvarindex1=newUSearchIndex(MetricKind.Cos,ScalarKind.Float32,128,reserve:1000);// Pre-allocate when loading from filevarindex2=newUSearchIndex("index.usearch",reserve:5000);// Pre-allocate with IndexOptionsvaroptions=newIndexOptions{/* ... */};varindex3=newUSearchIndex(options,reserve:2000);

Breaking Changes

None - this is a purely additive change with default parameter values.